use std::{collections::HashMap, path::Path, str::FromStr, sync::Arc};

use anyhow::{Context, Result, bail};
use nostr::{
    event::UnsignedEvent,
    nips::{nip01::Coordinate, nip10::Marker, nip19::Nip19},
};
use nostr_sdk::{
    Event, EventBuilder, EventId, FromBech32, Kind, NostrSigner, PublicKey, Tag, TagKind,
    TagStandard, hashes::sha1::Hash as Sha1Hash,
};

use crate::{
    cli_interactor::{Interactor, InteractorPrompt, PromptInputParms},
    client::sign_event,
    content_tags::tags_from_content,
    git::{Repo, RepoActions},
    repo_ref::RepoRef,
    utils::get_open_or_draft_proposals,
};

pub fn tag_value(event: &Event, tag_name: &str) -> Result<String> {
    Ok(event
        .tags
        .iter()
        .find(|t| !t.as_slice().is_empty() && t.as_slice()[0].eq(tag_name))
        .context(format!("tag '{tag_name}'not present"))?
        .as_slice()[1]
        .clone())
}

pub fn get_commit_id_from_patch(event: &Event) -> Result<String> {
    let value = tag_value(event, "commit");

    if value.is_ok() {
        value
    } else if event.content.starts_with("From ") && event.content.len().gt(&45) {
        Ok(event.content[5..45].to_string())
    } else {
        bail!("event is not a patch")
    }
}

pub fn get_parent_commit_from_patch(event: &Event, git_repo: Option<&Repo>) -> Result<String> {
    if let Ok(parent) = tag_value(event, "parent-commit") {
        return Ok(parent);
    }

    let metadata = crate::mbox_parser::parse_mbox_patch(&event.content)
        .context("failed to parse patch for timestamp")?;
    let timestamp = metadata
        .committer_timestamp
        .unwrap_or(metadata.author_timestamp);

    if let Some(repo) = git_repo {
        if let Some(best_guess) = repo
            .find_best_guess_parent_commit(timestamp)
            .context("failed to find best guess parent commit")?
        {
            return Ok(best_guess.to_string());
        }
    }

    bail!("no parent-commit tag and could not determine best guess parent")
}

pub fn get_event_root(event: &nostr::Event) -> Result<EventId> {
    Ok(EventId::parse(
        event
            .tags
            .iter()
            .find(|t| t.is_root())
            .context("no thread root in event")?
            .as_slice()
            .get(1)
            .unwrap(),
    )?)
}

pub fn status_kinds() -> Vec<Kind> {
    vec![
        Kind::GitStatusOpen,
        Kind::GitStatusApplied,
        Kind::GitStatusClosed,
        Kind::GitStatusDraft,
    ]
}

pub const KIND_PULL_REQUEST: Kind = Kind::Custom(1618);
pub const KIND_PULL_REQUEST_UPDATE: Kind = Kind::Custom(1619);
pub const KIND_USER_GRASP_LIST: Kind = Kind::Custom(10317);
/// NIP-22 comment (kind 1111) — threaded comments on any event.
pub const KIND_COMMENT: Kind = Kind::Custom(1111);
/// NIP-32 label event (kind 1985) — applies hashtag labels to an existing
/// event. Used to add labels to issues, patches and PRs after the fact.
pub const KIND_LABEL: Kind = Kind::Custom(1985);

pub fn event_is_patch_set_root(event: &Event) -> bool {
    event.kind.eq(&Kind::GitPatch)
        && event
            .tags
            .iter()
            .any(|t| t.as_slice().len() > 1 && t.as_slice()[1].eq("root"))
}

pub fn event_is_revision_root(event: &Event) -> bool {
    (event.kind.eq(&Kind::GitPatch)
        && event.tags.iter().any(|t| {
            t.as_slice().len() > 1
                && ["revision-root", "root-revision"].contains(&t.as_slice()[1].as_str())
        }))
        || (event.kind.eq(&KIND_PULL_REQUEST)
            && event
                .tags
                .iter()
                .any(|t| t.as_slice().len() > 1 && t.as_slice()[0].eq("e")))
}

pub fn patch_supports_commit_ids(event: &Event) -> bool {
    if !event.kind.eq(&Kind::GitPatch) {
        return false;
    }

    if event
        .tags
        .iter()
        .any(|t| !t.as_slice().is_empty() && t.as_slice()[0].eq("commit-pgp-sig"))
    {
        return true;
    }

    if event
        .tags
        .iter()
        .any(|t| !t.as_slice().is_empty() && t.as_slice()[0].eq("parent-commit"))
    {
        return true;
    }

    crate::mbox_parser::parse_mbox_patch(&event.content).is_ok()
}

pub fn event_is_valid_pr_or_pr_update(event: &Event) -> bool {
    [KIND_PULL_REQUEST, KIND_PULL_REQUEST_UPDATE].contains(&event.kind)
        && event.tags.iter().any(|t| {
            t.as_slice().len().gt(&1)
                && t.as_slice()[0].eq("c")
                && git2::Oid::from_str(&t.as_slice()[1]).is_ok()
        })
        && event
            .tags
            .iter()
            .any(|t| t.as_slice().len().gt(&1) && t.as_slice()[0].eq("clone"))
}

#[allow(clippy::too_many_arguments)]
#[allow(clippy::too_many_lines)]
pub async fn generate_patch_event(
    git_repo: &Repo,
    root_commit: &Sha1Hash,
    commit: &Sha1Hash,
    thread_event_id: Option<nostr::EventId>,
    signer: &Arc<dyn NostrSigner>,
    repo_ref: &RepoRef,
    parent_patch_event_id: Option<nostr::EventId>,
    series_count: Option<(u64, u64)>,
    branch_name: Option<String>,
    root_proposal_id: &Option<String>,
    mentions: &[nostr::Tag],
) -> Result<nostr::Event> {
    let commit_parent = git_repo
        .get_commit_parent(commit)
        .context("failed to get parent commit")?;
    let relay_hint = repo_ref.relays.first().cloned();

    // NIP-21 mention tags from commit message (description tag value, with mbox
    // fallback)
    let commit_message = git_repo.get_commit_message(commit).unwrap_or_default();
    let patch_content_tags = tags_from_content(&commit_message, git_repo.get_path().ok()).await?;

    let patch_tags = crate::content_tags::dedup_tags(
        [
            repo_ref
                .maintainers
                .iter()
                .map(|m| {
                    Tag::from_standardized(TagStandard::Coordinate {
                        coordinate: Coordinate {
                            kind: nostr::Kind::GitRepoAnnouncement,
                            public_key: *m,
                            identifier: repo_ref.identifier.to_string(),
                        },
                        relay_url: repo_ref.relays.first().cloned(),
                        uppercase: false,
                    })
                })
                .collect::<Vec<Tag>>(),
            vec![
                Tag::from_standardized(TagStandard::Reference(root_commit.to_string())),
                // commit id reference is a trade-off. its now
                // unclear which one is the root commit id but it
                // enables easier location of code comments againt
                // code that makes it into the main branch, assuming
                // the commit id is correct
                Tag::from_standardized(TagStandard::Reference(commit.to_string())),
                Tag::custom(
                    TagKind::Custom(std::borrow::Cow::Borrowed("alt")),
                    vec![format!(
                        "git patch: {}",
                        git_repo
                            .get_commit_message_summary(commit)
                            .unwrap_or_default()
                    )],
                ),
            ],
            if let Some(thread_event_id) = thread_event_id {
                vec![Tag::from_standardized(nostr_sdk::TagStandard::Event {
                    event_id: thread_event_id,
                    relay_url: relay_hint.clone(),
                    marker: Some(Marker::Root),
                    public_key: None,
                    uppercase: false,
                })]
            } else if let Some(event_ref) = root_proposal_id.clone() {
                vec![
                    Tag::hashtag("root"),
                    Tag::hashtag("root-revision"),
                    // TODO check if id is for a root proposal (perhaps its for an issue?)
                    event_tag_from_nip19_or_hex(
                        &event_ref,
                        "proposal",
                        EventRefType::Reply,
                        false,
                        false,
                    )?,
                ]
            } else {
                vec![Tag::hashtag("root")]
            },
            mentions.to_vec(),
            if let Some(id) = parent_patch_event_id {
                vec![Tag::from_standardized(nostr_sdk::TagStandard::Event {
                    event_id: id,
                    relay_url: relay_hint.clone(),
                    marker: Some(Marker::Reply),
                    public_key: None,
                    uppercase: false,
                })]
            } else {
                vec![]
            },
            // see comment on branch names in cover letter event creation
            if let Some(branch_name) = branch_name {
                if thread_event_id.is_none() {
                    vec![Tag::custom(
                        TagKind::Custom(std::borrow::Cow::Borrowed("branch-name")),
                        vec![branch_name.chars().take(60).collect::<String>()],
                    )]
                } else {
                    vec![]
                }
            } else {
                vec![]
            },
            // whilst it is in nip34 draft to tag the maintainers
            // I'm not sure it is a good idea because if they are
            // interested in all patches then their specialised
            // client should subscribe to patches tagged with the
            // repo reference. maintainers of large repos will not
            // be interested in every patch.
            repo_ref
                .maintainers
                .iter()
                .map(|pk| Tag::public_key(*pk))
                .collect(),
            vec![
                // a fallback is now in place to extract this from the patch
                Tag::custom(
                    TagKind::Custom(std::borrow::Cow::Borrowed("commit")),
                    vec![commit.to_string()],
                ),
                // this is required as patches cannot be relied upon to include the 'base
                // commit'
                Tag::custom(
                    TagKind::Custom(std::borrow::Cow::Borrowed("parent-commit")),
                    vec![commit_parent.to_string()],
                ),
                // this is required to ensure the commit id matches
                Tag::custom(
                    TagKind::Custom(std::borrow::Cow::Borrowed("commit-pgp-sig")),
                    vec![
                        git_repo
                            .extract_commit_pgp_signature(commit)
                            .unwrap_or_default(),
                    ],
                ),
                // removing description tag will not cause anything to break
                Tag::from_standardized(nostr_sdk::TagStandard::Description(
                    git_repo.get_commit_message(commit)?.to_string(),
                )),
                Tag::custom(
                    TagKind::Custom(std::borrow::Cow::Borrowed("author")),
                    git_repo.get_commit_author(commit)?,
                ),
                // this is required to ensure the commit id matches
                Tag::custom(
                    TagKind::Custom(std::borrow::Cow::Borrowed("committer")),
                    git_repo.get_commit_comitter(commit)?,
                ),
            ],
            patch_content_tags,
        ]
        .concat(),
    );

    sign_event(
        EventBuilder::new(
            nostr::event::Kind::GitPatch,
            git_repo
                .make_patch_from_commit(commit, &series_count)
                .context(format!("failed to make patch for commit {commit}"))?,
        )
        .tags(patch_tags),
        signer,
        if let Some((n, total)) = series_count {
            format!("commit {n}/{total}")
        } else {
            "commit 1/1".to_string()
        },
    )
    .await
    .context("failed to sign event")
}

#[derive(Debug, PartialEq)]
pub enum EventRefType {
    Root,
    Reply,
    Quote,
}

pub fn event_tag_from_nip19_or_hex(
    reference: &str,
    reference_name: &str,
    ref_type: EventRefType,
    allow_npub_reference: bool,
    prompt_for_correction: bool,
) -> Result<nostr::Tag> {
    let mut bech32 = reference.to_string();
    loop {
        if bech32.is_empty() {
            bech32 = Interactor::default().input(
                PromptInputParms::default().with_prompt(format!("{reference_name} reference")),
            )?;
        }
        let marker = match ref_type {
            EventRefType::Root => Some(Marker::Root),
            EventRefType::Reply => Some(Marker::Reply),
            EventRefType::Quote => None,
        };
        if let Ok(nip19) = Nip19::from_bech32(&bech32) {
            match nip19 {
                Nip19::Event(n) => {
                    if ref_type == EventRefType::Quote {
                        break Ok(Tag::from_standardized(nostr_sdk::TagStandard::Quote {
                            event_id: n.event_id,
                            relay_url: n.relays.first().cloned(),
                            public_key: None,
                        }));
                    }
                    break Ok(Tag::from_standardized(nostr_sdk::TagStandard::Event {
                        event_id: n.event_id,
                        relay_url: n.relays.first().cloned(),
                        marker,
                        public_key: None,
                        uppercase: false,
                    }));
                }
                Nip19::EventId(id) => {
                    if ref_type == EventRefType::Quote {
                        break Ok(Tag::from_standardized(nostr_sdk::TagStandard::Quote {
                            event_id: id,
                            relay_url: None,
                            public_key: None,
                        }));
                    }
                    break Ok(Tag::from_standardized(nostr_sdk::TagStandard::Event {
                        event_id: id,
                        relay_url: None,
                        marker,
                        public_key: None,
                        uppercase: false,
                    }));
                }
                Nip19::Coordinate(coordinate) => {
                    break Ok(Tag::from_standardized(TagStandard::Coordinate {
                        coordinate: coordinate.coordinate,
                        relay_url: coordinate.relays.first().cloned(),
                        uppercase: false,
                    }));
                }
                Nip19::Profile(profile) => {
                    if allow_npub_reference {
                        break Ok(Tag::public_key(profile.public_key));
                    }
                }
                Nip19::Pubkey(public_key) => {
                    if allow_npub_reference {
                        break Ok(Tag::public_key(public_key));
                    }
                }
                _ => {}
            }
        }
        if let Ok(id) = nostr::EventId::from_str(&bech32) {
            break Ok(Tag::from_standardized(nostr_sdk::TagStandard::Event {
                event_id: id,
                relay_url: None,
                marker,
                public_key: None,
                uppercase: false,
            }));
        }
        if prompt_for_correction {
            println!("not a valid {reference_name} event reference");
        } else {
            bail!(format!("not a valid {reference_name} event reference"));
        }

        bech32 = String::new();
    }
}

#[allow(clippy::too_many_arguments)]
pub async fn generate_unsigned_pr_or_update_event(
    git_repo: &Repo,
    repo_ref: &RepoRef,
    signing_public_key: &PublicKey,
    root_proposal: Option<&Event>,
    title_description_overide: &Option<(String, String)>,
    tip: &Sha1Hash,
    first_commit: &Sha1Hash,
    merge_base: Option<&Sha1Hash>,
    clone_url_hint: &[&str],
    mentions: &[nostr::Tag],
    git_repo_path: Option<&Path>,
) -> Result<UnsignedEvent> {
    let root_patch_cover_letter = if let Some(root_proposal) = root_proposal {
        if root_proposal.kind.eq(&Kind::GitPatch) {
            Some(event_to_cover_letter(root_proposal)?)
        } else {
            None
        }
    } else {
        None
    };

    let title = if let Some((title, _)) = &title_description_overide {
        title.clone()
    } else if let Some(cl) = &root_patch_cover_letter {
        cl.title.clone()
    } else {
        git_repo.get_commit_message_summary(first_commit)?
    };

    let description = if let Some((_, description)) = &title_description_overide {
        description.clone()
    } else if let Some(cl) = &root_patch_cover_letter {
        cl.description.clone()
    } else {
        let mut description = git_repo
            .get_commit_message(first_commit)?
            .trim()
            .to_string();
        if let Some(remaining_description) = description.strip_prefix(&title) {
            description = remaining_description.trim().to_string();
        }
        description
    };

    let root_commit = git_repo
        .get_root_commit()
        .context("failed to get root commit of the repository")?;

    let pr_update_specific_tags = |root_proposal: &Event| {
        vec![
            Tag::custom(
                nostr::TagKind::Custom(std::borrow::Cow::Borrowed("alt")),
                vec![format!("git Pull Request Update")],
            ),
            Tag::custom(
                nostr::TagKind::Custom(std::borrow::Cow::Borrowed("E")),
                vec![root_proposal.id],
            ),
            Tag::custom(
                nostr::TagKind::Custom(std::borrow::Cow::Borrowed("P")),
                vec![root_proposal.pubkey],
            ),
        ]
    };
    let pr_specific_tags = || {
        [
            vec![
                Tag::from_standardized(TagStandard::Subject(title.clone())),
                Tag::custom(
                    nostr::TagKind::Custom(std::borrow::Cow::Borrowed("alt")),
                    vec![format!("git Pull Request: {}", title.clone())],
                ),
            ],
            if let Some(cl) = &root_patch_cover_letter {
                vec![
                    Tag::custom(
                        nostr::TagKind::Custom(std::borrow::Cow::Borrowed("e")),
                        vec![root_proposal.unwrap().id],
                    ),
                    Tag::custom(
                        nostr::TagKind::Custom(std::borrow::Cow::Borrowed("branch-name")),
                        vec![cl.branch_name_without_id_or_prefix.clone()],
                    ),
                    Tag::public_key(root_proposal.unwrap().pubkey),
                ]
            } else if let Some(branch_name_tag) =
                make_branch_name_tag_from_check_out_branch(git_repo)
            {
                vec![branch_name_tag]
            } else {
                vec![]
            },
        ]
        .concat()
    };

    let merge_base_tag = if let Some(merge_base) = merge_base {
        vec![Tag::custom(
            nostr::TagKind::Custom(std::borrow::Cow::Borrowed("merge-base")),
            vec![format!("{merge_base}")],
        )]
    } else {
        vec![]
    };

    // NIP-21 mention tags from PR description content (only for new PRs, not
    // updates)
    let is_pr_update = root_proposal.is_some() && root_patch_cover_letter.is_none();
    let content_mention_tags = if is_pr_update {
        vec![]
    } else {
        tags_from_content(&description, git_repo_path).await?
    };

    let all_tags = crate::content_tags::dedup_tags(
        [
            repo_ref
                .maintainers
                .iter()
                .map(|m| {
                    Tag::from_standardized(TagStandard::Coordinate {
                        coordinate: Coordinate {
                            kind: nostr::Kind::GitRepoAnnouncement,
                            public_key: *m,
                            identifier: repo_ref.identifier.to_string(),
                        },
                        relay_url: repo_ref.relays.first().cloned(),
                        uppercase: false,
                    })
                })
                .collect::<Vec<Tag>>(),
            mentions.to_vec(),
            if let Some(root_proposal) = root_proposal {
                if root_patch_cover_letter.is_none() {
                    pr_update_specific_tags(root_proposal)
                } else {
                    pr_specific_tags()
                }
            } else {
                pr_specific_tags()
            },
            vec![
                Tag::from_standardized(TagStandard::Reference(format!("{root_commit}"))),
                Tag::custom(
                    nostr::TagKind::Custom(std::borrow::Cow::Borrowed("c")),
                    vec![format!("{tip}")],
                ),
                Tag::custom(
                    nostr::TagKind::Custom(std::borrow::Cow::Borrowed("clone")),
                    clone_url_hint
                        .iter()
                        .map(|s| s.to_string())
                        .collect::<Vec<String>>(),
                ),
            ],
            merge_base_tag,
            repo_ref
                .maintainers
                .iter()
                .map(|pk| Tag::public_key(*pk))
                .collect(),
            content_mention_tags,
        ]
        .concat(),
    );

    Ok(if is_pr_update {
        EventBuilder::new(KIND_PULL_REQUEST_UPDATE, "")
    } else {
        EventBuilder::new(KIND_PULL_REQUEST, description)
    }
    .tags(all_tags)
    .build(*signing_public_key))
}

fn make_branch_name_tag_from_check_out_branch(git_repo: &Repo) -> Option<Tag> {
    if let Ok(branch_name) = git_repo.get_checked_out_branch_name() {
        if !branch_name.eq("main")
            && !branch_name.eq("master")
            && !branch_name.eq("origin/main")
            && !branch_name.eq("origin/master")
        {
            Some(Tag::custom(
                nostr::TagKind::Custom(std::borrow::Cow::Borrowed("branch-name")),
                vec![
                    if let Some(branch_name) = branch_name.strip_prefix("pr/") {
                        branch_name.to_string()
                    } else {
                        branch_name
                    }
                    .chars()
                    .take(60)
                    .collect::<String>(),
                ],
            ))
        } else {
            None
        }
    } else {
        None
    }
}

#[allow(clippy::too_many_lines)]
pub async fn generate_cover_letter_and_patch_events(
    cover_letter_title_description: Option<(String, String)>,
    git_repo: &Repo,
    commits: &[Sha1Hash],
    signer: &Arc<dyn NostrSigner>,
    repo_ref: &RepoRef,
    root_proposal_id: &Option<String>,
    mentions: &[nostr::Tag],
) -> Result<Vec<nostr::Event>> {
    let git_repo_path = git_repo.get_path().ok();
    let root_commit = git_repo
        .get_root_commit()
        .context("failed to get root commit of the repository")?;

    let mut events = vec![];

    if let Some((title, description)) = cover_letter_title_description {
        // NIP-21 mention tags from cover letter title and description
        let cover_letter_text = format!("{title}\n\n{description}");
        let cover_letter_content_tags =
            tags_from_content(&cover_letter_text, git_repo_path).await?;

        let cover_letter_tags = crate::content_tags::dedup_tags(
            [
                repo_ref
                    .maintainers
                    .iter()
                    .map(|m| {
                        Tag::from_standardized(TagStandard::Coordinate {
                            coordinate: Coordinate {
                                kind: nostr::Kind::GitRepoAnnouncement,
                                public_key: *m,
                                identifier: repo_ref.identifier.to_string(),
                            },
                            relay_url: repo_ref.relays.first().cloned(),
                            uppercase: false,
                        })
                    })
                    .collect::<Vec<Tag>>(),
                vec![
                    Tag::from_standardized(TagStandard::Reference(format!("{root_commit}"))),
                    Tag::hashtag("cover-letter"),
                    Tag::custom(
                        nostr::TagKind::Custom(std::borrow::Cow::Borrowed("alt")),
                        vec![format!("git patch cover letter: {}", title.clone())],
                    ),
                ],
                if let Some(event_ref) = root_proposal_id.clone() {
                    vec![
                        Tag::hashtag("root"),
                        Tag::hashtag("root-revision"),
                        // TODO check if id is for a root proposal (perhaps its for an issue?)
                        event_tag_from_nip19_or_hex(
                            &event_ref,
                            "proposal",
                            EventRefType::Reply,
                            false,
                            false,
                        )?,
                    ]
                } else {
                    vec![Tag::hashtag("root")]
                },
                mentions.to_vec(),
                // this is not strictly needed but makes for prettier branch names
                // eventually a prefix will be needed of the event id to stop 2 proposals with the
                // same name colliding a change like this, or the removal of this
                // tag will require the actual branch name to be tracked so pulling
                // and pushing still work
                if let Some(branch_name_tag) = make_branch_name_tag_from_check_out_branch(git_repo)
                {
                    vec![branch_name_tag]
                } else {
                    vec![]
                },
                repo_ref
                    .maintainers
                    .iter()
                    .map(|pk| Tag::public_key(*pk))
                    .collect(),
                cover_letter_content_tags,
            ]
            .concat(),
        );

        events.push(sign_event(EventBuilder::new(
        nostr::event::Kind::GitPatch,
        format!(
            "From {} Mon Sep 17 00:00:00 2001\nSubject: [PATCH 0/{}] {title}\n\n{description}",
            commits.last().unwrap(),
            commits.len()
        ))
        .tags(cover_letter_tags),
    signer,
    format!("commit 0/{}",commits.len()),
).await
    .context("failed to create cover-letter event")?);
    }

    for (i, commit) in commits.iter().enumerate() {
        events.push(
            generate_patch_event(
                git_repo,
                &root_commit,
                commit,
                events.first().map(|event| event.id),
                signer,
                repo_ref,
                events.last().map(|e| e.id),
                if events.is_empty() && commits.len().eq(&1) {
                    None
                } else {
                    Some(((i + 1).try_into()?, commits.len().try_into()?))
                },
                if events.is_empty() {
                    if let Ok(branch_name) = git_repo.get_checked_out_branch_name() {
                        if !branch_name.eq("main")
                            && !branch_name.eq("master")
                            && !branch_name.eq("origin/main")
                            && !branch_name.eq("origin/master")
                        {
                            Some(
                                if let Some(branch_name) = branch_name.strip_prefix("pr/") {
                                    branch_name.to_string()
                                } else {
                                    branch_name
                                }
                                .chars()
                                .take(60)
                                .collect::<String>(),
                            )
                        } else {
                            None
                        }
                    } else {
                        None
                    }
                } else {
                    None
                },
                root_proposal_id,
                if events.is_empty() { mentions } else { &[] },
            )
            .await
            .context("failed to generate patch event")?,
        );
    }
    Ok(events)
}

pub struct CoverLetter {
    pub title: String,
    pub description: String,
    pub branch_name_without_id_or_prefix: String,
    pub event_id: Option<nostr::EventId>,
}

impl CoverLetter {
    pub fn get_branch_name_with_pr_prefix_and_shorthand_id(&self) -> Result<String> {
        Ok(format!(
            "pr/{}({})",
            self.branch_name_without_id_or_prefix,
            &self
                .event_id
                .context("proposal root event_id must be know to get it's branch name")?
                .to_hex()
                .as_str()[..8],
        ))
    }
}
pub fn event_is_cover_letter(event: &nostr::Event) -> bool {
    // TODO: look for Subject:[ PATCH 0/n ] but watch out for:
    //   [PATCH v1 0/n ] or
    //   [PATCH subsystem v2 0/n ]
    event.kind.eq(&Kind::GitPatch)
        && event
            .tags
            .iter()
            .any(|t| t.as_slice().len() > 1 && t.as_slice()[1].eq("root"))
        && event
            .tags
            .iter()
            .any(|t| t.as_slice().len() > 1 && t.as_slice()[1].eq("cover-letter"))
}

pub fn commit_msg_from_patch(patch: &nostr::Event) -> Result<String> {
    if let Ok(msg) = tag_value(patch, "description") {
        Ok(msg)
    } else {
        let start_index = patch
            .content
            .find("] ")
            .context("event is not formatted as a patch or cover letter")?
            + 2;
        let end_index = patch.content[start_index..]
            .find("\ndiff --git")
            .unwrap_or(patch.content.len());
        Ok(patch.content[start_index..end_index].to_string())
    }
}

pub fn commit_msg_from_patch_oneliner(patch: &nostr::Event) -> Result<String> {
    Ok(commit_msg_from_patch(patch)?
        .split('\n')
        .collect::<Vec<&str>>()[0]
        .to_string())
}

pub fn event_to_cover_letter(event: &nostr::Event) -> Result<CoverLetter> {
    if !event.kind.eq(&KIND_PULL_REQUEST) && !event_is_patch_set_root(event) {
        bail!("event is not a patch set root event (root patch or cover letter)")
    }

    let title = if event.kind.eq(&KIND_PULL_REQUEST) {
        tag_value(event, "subject").unwrap_or("untitled".to_owned())
    } else {
        commit_msg_from_patch_oneliner(event)?
    };
    let description = if event.kind.eq(&KIND_PULL_REQUEST) {
        event.content.clone()
    } else {
        commit_msg_from_patch(event)?[title.len()..]
            .trim()
            .to_string()
    };

    Ok(CoverLetter {
        title: title.clone(),
        description,
        branch_name_without_id_or_prefix: if let Ok(name) = tag_value(event, "branch-name") {
            if !name.eq("main") && !name.eq("master") {
                safe_branch_name_for_pr(&name)
            } else {
                safe_branch_name_for_pr(&title)
            }
        } else {
            safe_branch_name_for_pr(&title)
        },
        event_id: Some(event.id),
    })
}

fn safe_branch_name_for_pr(s: &str) -> String {
    s.replace(' ', "-")
        .chars()
        .map(|c| {
            if c.is_ascii_alphanumeric() || c.eq(&'/') {
                c
            } else {
                '-'
            }
        })
        .take(60)
        .collect()
}

pub fn get_pr_tip_event_or_most_recent_patch_with_ancestors(
    mut proposal_events: Vec<nostr::Event>,
) -> Result<Vec<nostr::Event>> {
    proposal_events.sort_by_key(|e| e.created_at);

    let youngest = proposal_events.last().context("no proposal events found")?;

    let events_with_youngest_created_at: Vec<&nostr::Event> = proposal_events
        .iter()
        .filter(|p| p.created_at.eq(&youngest.created_at))
        .collect();

    let mut res = vec![];

    let mut event_id_to_search = events_with_youngest_created_at
        .clone()
        .iter()
        .find(|p| {
            !events_with_youngest_created_at.iter().any(|p2| {
                if let Ok(reply_to) = get_event_parent_id(p2) {
                    reply_to.eq(&p.id.to_string())
                } else {
                    false
                }
            })
        })
        .context("failed to find events_with_youngest_created_at")?
        .id
        .to_string();

    while let Some(event) = proposal_events
        .iter()
        .find(|e| e.id.to_string().eq(&event_id_to_search))
    {
        res.push(event.clone());
        if [KIND_PULL_REQUEST, KIND_PULL_REQUEST_UPDATE].contains(&event.kind)
            || event_is_patch_set_root(event)
        {
            break;
        }
        event_id_to_search = get_event_parent_id(event).unwrap_or_default();
    }
    Ok(res)
}

fn get_event_parent_id(event: &nostr::Event) -> Result<String> {
    Ok(if let Some(reply_tag) = event
        .tags
        .iter()
        .find(|t| t.as_slice().len().gt(&3) && t.as_slice()[3].eq("reply"))
    {
        reply_tag
    } else {
        event
            .tags
            .iter()
            .find(|t| t.as_slice().len().gt(&3) && t.as_slice()[3].eq("root"))
            .context("no reply or root e tag present".to_string())?
    }
    .as_slice()[1]
        .clone())
}

pub fn is_event_proposal_root_for_branch(
    e: &Event,
    branch_name_or_refstr: &str,
    logged_in_user: Option<&PublicKey>,
) -> Result<bool> {
    let branch_name = branch_name_or_refstr.replace("refs/heads/", "");
    Ok(event_to_cover_letter(e).is_ok_and(|cl| {
        (logged_in_user.is_some_and(|public_key| e.pubkey.eq(public_key))
            && branch_name.eq(&format!("pr/{}", cl.branch_name_without_id_or_prefix)))
            || cl
                .get_branch_name_with_pr_prefix_and_shorthand_id()
                .is_ok_and(|s| s.eq(&branch_name))
    }) && (
        // If we wanted to treat to list Pull Requests that revise a Patch we would do this:
        // Note: whilst this the the case elsewhere event_is_revision_root is used, there is more to
        //       think about here?
        // e.kind.eq(&KIND_PULL_REQUEST) ||
        !event_is_revision_root(e)
    ))
}

/// Process hashtag labels (`#t` namespace) from a pre-fetched set of kind-1985
/// events.
///
/// Labels come from two sources, both subject to the same permission check:
///
/// 1. `t` tags on the event itself (self-reported by the event author).
/// 2. NIP-32 kind-1985 label events in `label_events` that reference `event`
///    via a lowercase `e` tag and carry `["L", "#t"]` +
///    `["l", "<value>", "#t"]` tags.
///
/// A label is only applied when the author of the source event is either the
/// author of `event` itself or one of the repository maintainers.
///
/// Labels are additive — all valid label events contribute; there is no
/// "latest wins" replacement semantics.
pub fn process_labels(
    event: &Event,
    repo_ref: &RepoRef,
    label_events: &[Event],
) -> Vec<String> {
    let is_permitted = |pubkey: &PublicKey| -> bool {
        pubkey.eq(&event.pubkey) || repo_ref.maintainers.contains(pubkey)
    };

    // 1. Inline `t` tags on the event itself.
    let mut labels: Vec<String> = if is_permitted(&event.pubkey) {
        event
            .tags
            .iter()
            .filter(|t| {
                let s = t.as_slice();
                s.len() >= 2 && s[0].eq("t")
            })
            .map(|t| t.as_slice()[1].clone())
            .collect()
    } else {
        vec![]
    };

    // 2. External NIP-32 kind-1985 label events (`#t` namespace).
    //
    // A valid label event must:
    //   - be kind 1985
    //   - reference `event` via a lowercase `e` tag
    //   - have `["L", "#t"]` (namespace declaration)
    //   - have at least one `["l", "<value>", "#t"]` tag
    //   - be authored by a permitted pubkey
    let event_id_str = event.id.to_string();
    for label_event in label_events {
        if !label_event.kind.eq(&KIND_LABEL) {
            continue;
        }
        if !is_permitted(&label_event.pubkey) {
            continue;
        }
        // Must reference our event via a lowercase `e` tag.
        let references_event = label_event.tags.iter().any(|t| {
            let s = t.as_slice();
            s.len() >= 2 && s[0].eq("e") && s[1].eq(&event_id_str)
        });
        if !references_event {
            continue;
        }
        // Must declare the `#t` namespace.
        let has_namespace = label_event.tags.iter().any(|t| {
            let s = t.as_slice();
            s.len() >= 2 && s[0].eq("L") && s[1].eq("#t")
        });
        if !has_namespace {
            continue;
        }
        // Collect all `["l", "<value>", "#t"]` labels from this event.
        for tag in label_event.tags.iter() {
            let s = tag.as_slice();
            if s.len() >= 3 && s[0].eq("l") && s[2].eq("#t") && !s[1].is_empty() {
                let label = s[1].clone();
                if !labels.contains(&label) {
                    labels.push(label);
                }
            }
        }
    }

    labels
}

/// Process the effective subject/title override for `event` from a pre-fetched
/// set of kind-1985 events.
///
/// Subject overrides use the `#subject` namespace:
///   `["L", "#subject"]` + `["l", "<new title>", "#subject"]`
///
/// Unlike hashtag labels, subject overrides are replaceable-style: only the
/// latest authorised event wins, with tiebreak by lexicographically larger
/// event ID (consistent with NIP-1 replaceable event semantics).
///
/// Only the author of `event` or a repository maintainer may set the subject.
/// Returns `None` when no valid subject override exists.
pub fn process_subject(
    event: &Event,
    repo_ref: &RepoRef,
    label_events: &[Event],
) -> Option<String> {
    let is_permitted = |pubkey: &PublicKey| -> bool {
        pubkey.eq(&event.pubkey) || repo_ref.maintainers.contains(pubkey)
    };

    let event_id_str = event.id.to_string();

    // Find the winning subject label event: latest created_at, tiebreak by
    // lexicographically larger event ID (NIP-1 replaceable event semantics).
    let winner = label_events
        .iter()
        .filter(|le| {
            if !le.kind.eq(&KIND_LABEL) {
                return false;
            }
            if !is_permitted(&le.pubkey) {
                return false;
            }
            // Must reference our event via a lowercase `e` tag.
            let references_event = le.tags.iter().any(|t| {
                let s = t.as_slice();
                s.len() >= 2 && s[0].eq("e") && s[1].eq(&event_id_str)
            });
            if !references_event {
                return false;
            }
            // Must declare the `#subject` namespace.
            let has_namespace = le.tags.iter().any(|t| {
                let s = t.as_slice();
                s.len() >= 2 && s[0].eq("L") && s[1].eq("#subject")
            });
            if !has_namespace {
                return false;
            }
            // Must have at least one non-empty `["l", "<value>", "#subject"]` tag.
            le.tags.iter().any(|t| {
                let s = t.as_slice();
                s.len() >= 3 && s[0].eq("l") && s[2].eq("#subject") && !s[1].is_empty()
            })
        })
        .max_by(|a, b| {
            // Primary: newer created_at wins.
            // Tiebreak: lexicographically larger event ID wins (NIP-1).
            a.created_at
                .cmp(&b.created_at)
                .then_with(|| a.id.to_string().cmp(&b.id.to_string()))
        })?;

    // Extract the subject value from the winning event.
    winner.tags.iter().find_map(|t| {
        let s = t.as_slice();
        if s.len() >= 3 && s[0].eq("l") && s[2].eq("#subject") && !s[1].is_empty() {
            Some(s[1].clone())
        } else {
            None
        }
    })
}

/// Compute both the effective hashtag labels and the subject/title override for
/// `event` from a pre-fetched set of kind-1985 events.
///
/// This is the primary entry point: callers should fetch label events once
/// (covering both `#t` and `#subject` namespaces) and pass them here to get
/// both results in a single pass.
///
/// Returns `(labels, subject_override)` where `subject_override` is `None`
/// when no authorised `#subject` label exists.
pub fn get_labels_and_subject(
    event: &Event,
    repo_ref: &RepoRef,
    label_events: &[Event],
) -> (Vec<String>, Option<String>) {
    (
        process_labels(event, repo_ref, label_events),
        process_subject(event, repo_ref, label_events),
    )
}

/// Compatibility wrapper — returns only the hashtag labels.
///
/// Prefer [`get_labels_and_subject`] when the subject override is also needed.
pub fn get_labels(
    event: &Event,
    repo_ref: &RepoRef,
    label_events: &[Event],
) -> Vec<String> {
    process_labels(event, repo_ref, label_events)
}

pub fn get_status(
    proposal: &Event,
    repo_ref: &RepoRef,
    all_status_in_repo: &[Event],
    all_pr_roots_in_repo: &[Event],
) -> Kind {
    let get_direct_status = |proposal: &Event| {
        if let Some(e) = all_status_in_repo
            .iter()
            .filter(|e| {
                status_kinds().contains(&e.kind)
                    && e.tags.iter().any(|t| {
                        t.as_slice().len() > 1 && t.as_slice()[1].eq(&proposal.id.to_string())
                    })
                    && (proposal.pubkey.eq(&e.pubkey) || repo_ref.maintainers.contains(&e.pubkey))
            })
            .collect::<Vec<&nostr::Event>>()
            .first()
        {
            e.kind
        } else {
            Kind::GitStatusOpen
        }
    };
    let is_proposal_pr_revision_of_patch = |proposal: &Event, patch: &Event| {
        proposal.kind.eq(&KIND_PULL_REQUEST)
            && proposal.tags.clone().into_iter().any(|t| {
                t.as_slice().len() > 1
                    && t.as_slice()[0].eq("e")
                    && t.as_slice()[1].eq(&patch.id.to_string())
            })
    };

    let direct_status = get_direct_status(proposal);
    if direct_status.eq(&Kind::GitStatusClosed) && proposal.kind.eq(&Kind::GitPatch) {
        if let Some(pr_revision) = all_pr_roots_in_repo
            .iter()
            .find(|p| is_proposal_pr_revision_of_patch(p, proposal))
        {
            get_direct_status(pr_revision)
        } else {
            direct_status
        }
    } else {
        direct_status
    }
}

pub async fn identify_clone_urls_for_oids_from_pr_pr_update_events(
    oids: Vec<&String>,
    git_repo: &Repo,
    repo_ref: &RepoRef,
) -> Result<HashMap<String, Vec<String>>> {
    let mut map: HashMap<String, Vec<String>> = HashMap::new();

    let open_and_draft_proposals = get_open_or_draft_proposals(git_repo, repo_ref).await?;

    for (_, (_, events)) in open_and_draft_proposals {
        for event in events {
            if [KIND_PULL_REQUEST, KIND_PULL_REQUEST_UPDATE].contains(&event.kind) {
                if let Ok(c) = tag_value(&event, "c") {
                    if oids.contains(&&c) {
                        for tag in event.tags.as_slice() {
                            if tag.kind().eq(&nostr::event::TagKind::Clone) {
                                for clone_url in tag.as_slice().iter().skip(1) {
                                    map.entry(c.clone()).or_default().push(clone_url.clone());
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    Ok(map)
}

#[cfg(test)]
mod tests {
    use super::*;

    mod event_to_cover_letter {
        use super::*;

        fn generate_cover_letter(title: &str, description: &str) -> Result<nostr::Event> {
            Ok(nostr::event::EventBuilder::new(
                nostr::event::Kind::GitPatch,
                format!("From ea897e987ea9a7a98e7a987e97987ea98e7a3334 Mon Sep 17 00:00:00 2001\nSubject: [PATCH 0/2] {title}\n\n{description}"),
                )
            .tags([
                    Tag::hashtag("cover-letter"),
                    Tag::hashtag("root"),
                ],
            )
            .sign_with_keys(&nostr::Keys::generate())?)
        }

        #[test]
        fn basic_title() -> Result<()> {
            assert_eq!(
                event_to_cover_letter(&generate_cover_letter("the title", "description here")?)?
                    .title,
                "the title",
            );
            Ok(())
        }

        #[test]
        fn basic_description() -> Result<()> {
            assert_eq!(
                event_to_cover_letter(&generate_cover_letter("the title", "description here")?)?
                    .description,
                "description here",
            );
            Ok(())
        }

        #[test]
        fn description_trimmed() -> Result<()> {
            assert_eq!(
                event_to_cover_letter(&generate_cover_letter(
                    "the title",
                    " \n \ndescription here\n\n "
                )?)?
                .description,
                "description here",
            );
            Ok(())
        }

        #[test]
        fn multi_line_description() -> Result<()> {
            assert_eq!(
                event_to_cover_letter(&generate_cover_letter(
                    "the title",
                    "description here\n\nmore here\nmore"
                )?)?
                .description,
                "description here\n\nmore here\nmore",
            );
            Ok(())
        }

        #[test]
        fn new_lines_in_title_forms_part_of_description() -> Result<()> {
            assert_eq!(
                event_to_cover_letter(&generate_cover_letter(
                    "the title\nwith new line",
                    "description here\n\nmore here\nmore"
                )?)?
                .title,
                "the title",
            );
            assert_eq!(
                event_to_cover_letter(&generate_cover_letter(
                    "the title\nwith new line",
                    "description here\n\nmore here\nmore"
                )?)?
                .description,
                "with new line\n\ndescription here\n\nmore here\nmore",
            );
            Ok(())
        }

        mod blank_description {
            use super::*;

            #[test]
            fn title_correct() -> Result<()> {
                assert_eq!(
                    event_to_cover_letter(&generate_cover_letter("the title", "")?)?.title,
                    "the title",
                );
                Ok(())
            }

            #[test]
            fn description_is_empty_string() -> Result<()> {
                assert_eq!(
                    event_to_cover_letter(&generate_cover_letter("the title", "")?)?.description,
                    "",
                );
                Ok(())
            }
        }
    }
}