//! Projects (hub spec §8.2): boards of issues, proposals and notes across

//! the repositories of one person or organisation.

use super::settings::csrf;

use super::{filters, Error, Page, Shell};

use crate::auth::{roles, Access, Viewer};

use crate::db::{self, issues as idb, projects as pdb};

use crate::Shared;

use askama::Template;

use axum::extract::{Form, Path, Query, State};

use axum::response::{IntoResponse, Redirect, Response};

use serde::Deserialize;

/// What a caller may do with an owner's projects.

pub struct Rights {

    /// Sees private projects.

    pub member: bool,

    /// Creates and changes projects.

    pub edit: bool,

}

/// Rights of `account` (anonymous when `None`) over `owner`'s projects;

/// `None` when there is no such person or organisation.

pub async fn rights_of(app: &Shared, account: Option<&db::accounts::Account>, owner: &str) -> sqlx::Result<Option<Rights>> {

    let admin = account.is_some_and(|a| a.is_admin);

    if let Some(a) = db::accounts::account_by_name(&app.db, owner).await? {

        let me = account.is_some_and(|v| v.id == a.id);

        return Ok(Some(Rights { member: me || admin, edit: me || admin }));

    }

    if let Some(o) = db::accounts::org_by_name(&app.db, owner).await? {

        let member = match account {

            Some(v) => db::accounts::org_role(&app.db, o.id, v.id).await?.is_some(),

            None => false,

        };

        return Ok(Some(Rights { member: member || admin, edit: member || admin }));

    }

    Ok(None)

}

async fn rights(app: &Shared, shell: &Shell, viewer: &Viewer, owner: &str) -> Result<Rights, Error> {

    rights_of(app, viewer.account(), owner)

        .await

        .map_err(|e| Error::from_db(shell.clone(), e))?

        .ok_or_else(|| Error::not_found(shell.clone()))

}

#[derive(Template)]

#[template(path = "projects.html")]

pub struct ProjectsPage {

    shell: Shell,

    owner: String,

    /// The projects shown: open or closed as `closed` says, matching `q`.

    projects: Vec<pdb::Project>,

    can_edit: bool,

    error: Option<String>,

    /// On your own page, the organisations you belong to: their boards

    /// are one click away, and where a board for one is made (#119).

    orgs: Vec<String>,

    /// The title filter, and whether the closed ones are shown (#124).

    q: String,

    closed: bool,

    open_count: usize,

    closed_count: usize,

}

impl ProjectsPage {

    /// The page for `all` the projects the viewer may see: counted open

    /// and closed among those matching `q`, then the ones asked for.

    #[allow(clippy::too_many_arguments)]

    fn build(

        shell: Shell,

        owner: String,

        all: Vec<pdb::Project>,

        can_edit: bool,

        error: Option<String>,

        orgs: Vec<String>,

        q: Option<String>,

        closed: bool,

    ) -> ProjectsPage {

        let q = q.unwrap_or_default().trim().to_string();

        let needle = q.to_lowercase();

        let matching: Vec<pdb::Project> = all

            .into_iter()

            .filter(|p| needle.is_empty() || p.title.to_lowercase().contains(&needle) || p.description.to_lowercase().contains(&needle))

            .collect();

        let closed_count = matching.iter().filter(|p| p.closed).count();

        let open_count = matching.len() - closed_count;

        let projects = matching.into_iter().filter(|p| p.closed == closed).collect();

        ProjectsPage { shell, owner, projects, can_edit, error, orgs, q, closed, open_count, closed_count }

    }

}

/// `?q=TEXT&state=open|closed` on the Projects page (#124).

#[derive(Deserialize, Default)]

pub struct ProjectsQuery {

    #[serde(default)]

    q: Option<String>,

    #[serde(default)]

    state: Option<String>,

}

/// The organisations the viewer belongs to, when `owner` is the viewer.

async fn own_orgs(app: &Shared, viewer: &Viewer, owner: &str) -> Vec<String> {

    match viewer.account() {

        Some(a) if a.username == owner => {

            crate::db::accounts::orgs_of(&app.db, a.id).await.map(|v| v.into_iter().map(|(o, _)| o.name).collect()).unwrap_or_default()

        }

        _ => vec![],

    }

}

pub async fn list(

    State(app): State<Shared>,

    viewer: Viewer,

    Path(owner): Path<String>,

    Query(query): Query<ProjectsQuery>,

) -> Result<Page<ProjectsPage>, Error> {

    let shell = Shell::new(&app, &format!("/projects/{owner}"), &viewer);

    let r = rights(&app, &shell, &viewer, &owner).await?;

    let projects = pdb::of_owner(&app.db, &owner)

        .await

        .map_err(|e| Error::from_db(shell.clone(), e))?

        .into_iter()

        .filter(|p| p.public || r.member)

        .collect();

    let orgs = own_orgs(&app, &viewer, &owner).await;

    let closed = query.state.as_deref() == Some("closed");

    Ok(Page(ProjectsPage::build(shell, owner, projects, r.edit, None, orgs, query.q, closed)))

}

#[derive(Deserialize)]

pub struct NewProjectForm {

    #[serde(rename = "_csrf")]

    csrf_token: String,

    title: String,

    #[serde(default)]

    description: String,

    #[serde(default)]

    private: Option<String>,

}

pub async fn create(

    State(app): State<Shared>,

    viewer: Viewer,

    Path(owner): Path<String>,

    Form(f): Form<NewProjectForm>,

) -> Result<Response, Error> {

    let shell = Shell::new(&app, &format!("/projects/{owner}"), &viewer);

    csrf(&viewer, &f.csrf_token, &shell)?;

    let r = rights(&app, &shell, &viewer, &owner).await?;

    if !r.edit {

        return Err(Error::not_found(shell));

    }

    let title = f.title.trim();

    if title.is_empty() || title.len() > 100 {

        let projects = pdb::of_owner(&app.db, &owner).await.map_err(|e| Error::from_db(shell.clone(), e))?;

        let orgs = own_orgs(&app, &viewer, &owner).await;

        return Ok(Page(ProjectsPage::build(

            shell,

            owner,

            projects,

            true,

            Some("A project needs a title of up to 100 characters.".into()),

            orgs,

            None,

            false,

        ))

        .into_response());

    }

    let p = pdb::create(&app.db, &owner, title, f.description.trim(), f.private.is_none())

        .await

        .map_err(|e| Error::from_db(shell.clone(), e))?;

    db::accounts::audit(&app.db, viewer.account(), "project.created", &format!("{owner}/{}", p.number), title).await.ok();

    Ok(Redirect::to(&format!("/projects/{owner}/{}", p.number)).into_response())

}

/// A card as the board shows it.

pub struct CardView {

    pub card: pdb::Card,

    /// `owner/name#N`, for issue and proposal cards.

    pub reference: String,

    pub url: String,

    pub title: String,

    /// `open`, `closed`, `landed`, `draft`… for issues and proposals.

    pub state: String,

    /// The issue's or proposal's labels, and an issue's assignees (#293).

    pub labels: Vec<idb::Label>,

    pub assignees: Vec<String>,

}

pub struct ColumnView {

    pub column: pdb::Column,

    pub cards: Vec<CardView>,

    /// Cards the page leaves out (#293): the oldest of a long column, or

    /// those a filter does not match; `total` is how many it holds.

    pub hidden: usize,

    pub total: usize,

    /// Its archived cards (#293), shown on the archive view.

    pub archived: usize,

    /// Its cards are all finished work (a Done column): its note says

    /// they are archived after a fortnight unless it says otherwise.

    pub finished: bool,

}

/// A column longer than this shows its newest cards only, with "show all"

/// (#293): a board's Done column otherwise grows without end.

pub const COLUMN_SHOWN: usize = 30;

/// How the board page shows its cards (#293).

#[derive(Deserialize, Default)]

pub struct BoardQuery {

    /// The column shown whole.

    #[serde(default)]

    all: Option<i64>,

    /// Only cards whose title or reference holds these words, and with

    /// `label:NAME`, `assignee:NAME` or `state:STATE` as the issue list takes.

    #[serde(default)]

    q: Option<String>,

    /// Only cards in this state (`open`, `closed`, `landed`…).

    #[serde(default)]

    state: Option<String>,

    /// The archived cards instead (`?archived=1`).

    #[serde(default)]

    archived: Option<String>,

    /// A past iteration: the cards archived under it, and its burn-up (#343).

    #[serde(default)]

    iteration: Option<i64>,

}

impl BoardQuery {

    fn text(&self) -> String {

        self.q.as_deref().map(str::trim).unwrap_or("").to_string()

    }

    fn state(&self) -> String {

        self.state.as_deref().map(str::trim).unwrap_or("").to_ascii_lowercase()

    }

    fn archived(&self) -> bool {

        self.archived.as_deref().is_some_and(|a| !a.is_empty() && a != "0")

    }

}

/// The board filter's `label:`, `assignee:` and `state:` terms, and its words.

#[derive(Default)]

struct CardFilter {

    labels: Vec<String>,

    assignees: Vec<String>,

    state: String,

    words: Vec<String>,

}

impl CardFilter {

    fn of(view: &BoardQuery) -> CardFilter {

        let mut f = CardFilter { state: view.state(), ..Default::default() };

        for tok in view.text().split_whitespace() {

            match tok.split_once(':') {

                Some(("label", v)) if !v.is_empty() => f.labels.push(v.to_lowercase()),

                Some(("assignee", v)) if !v.is_empty() => f.assignees.push(v.trim_start_matches('@').to_lowercase()),

                Some(("state", v)) if !v.is_empty() => f.state = v.to_lowercase(),

                _ => f.words.push(tok.to_lowercase()),

            }

        }

        f

    }

    fn is_empty(&self) -> bool {

        self.labels.is_empty() && self.assignees.is_empty() && self.state.is_empty() && self.words.is_empty()

    }

    /// Every term holds: each word in the title or reference, each label

    /// and assignee among the card's, and its state.

    fn keeps(&self, c: &CardView) -> bool {

        let (title, reference) = (c.title.to_lowercase(), c.reference.to_lowercase());

        self.words.iter().all(|w| title.contains(w) || reference.contains(w))

            && self.labels.iter().all(|l| c.labels.iter().any(|x| x.name.eq_ignore_ascii_case(l)))

            && self.assignees.iter().all(|a| c.assignees.iter().any(|x| x.eq_ignore_ascii_case(a)))

            && (self.state.is_empty() || c.state.eq_ignore_ascii_case(&self.state))

    }

}

/// Filter and cut the columns as `view` says.

fn shape(columns: &mut [ColumnView], view: &BoardQuery) {

    let filter = CardFilter::of(view);

    for col in columns.iter_mut() {

        col.total = col.cards.len();

        if !filter.is_empty() {

            col.cards.retain(|c| filter.keeps(c));

        } else if col.cards.len() > COLUMN_SHOWN && view.all != Some(col.column.id) && !view.archived() && view.iteration.is_none() {

            // Cards join a column at its end: the newest are the last.

            let cut = col.cards.len() - COLUMN_SHOWN;

            col.cards.drain(..cut);

        }

        col.hidden = col.total - col.cards.len();

    }

}

/// An iteration as the board shows it (#343).

pub struct IterationView {

    pub it: pdb::Iteration,

    /// Its first and last days, YYYY-MM-DD.

    pub first: String,

    pub last: String,

    pub days: i64,

    /// Its days so far (all of them once it has ended).

    pub so_far: usize,

    /// Cards done in it so far.

    pub done: usize,

    /// The burn-up as SVG polyline points in a [`BURN_W`] × [`BURN_H`] box,

    /// one point per day so far; `top` is the count at the top of the box.

    pub points: String,

    pub top: usize,

}

pub const BURN_W: i64 = 280;

pub const BURN_H: i64 = 64;

/// How many past iterations the board lists.

const PAST_SHOWN: usize = 12;

const DAY_MS: i64 = 86_400_000;

/// `YYYY-MM-DD` to the midnight (UTC) that starts it.

fn day_ms(s: &str) -> Option<i64> {

    let mut parts = s.trim().splitn(3, '-').map(|p| p.parse::<i32>().ok());

    let (y, m, d) = (parts.next()??, parts.next()??, parts.next()??);

    let month = time::Month::try_from(u8::try_from(m).ok()?).ok()?;

    let date = time::Date::from_calendar_date(y, month, u8::try_from(d).ok()?).ok()?;

    Some(date.midnight().assume_utc().unix_timestamp() * 1000)

}

/// The day (UTC) holding `ms`, as `YYYY-MM-DD`.

fn day_of(ms: i64) -> String {

    let t = time::OffsetDateTime::from_unix_timestamp(ms.div_euclid(1000)).unwrap_or(time::OffsetDateTime::UNIX_EPOCH);

    format!("{:04}-{:02}-{:02}", t.year(), u8::from(t.month()), t.day())

}

async fn iteration_view(app: &Shared, it: pdb::Iteration, done: Option<i64>, now: i64) -> sqlx::Result<IterationView> {

    let times = pdb::done_times(&app.db, &it, done).await?;

    let days = pdb::iteration_days(&it);

    let up = pdb::burn_up(&times, it.start_ms, it.end_ms, it.closed_ms.unwrap_or(now));

    let top = up.last().copied().unwrap_or(0).max(1);

    // From nothing at the start to each day's end.

    let points = std::iter::once((0, 0))

        .chain(up.iter().enumerate().map(|(d, &n)| (d as i64 + 1, n)))

        .map(|(d, n)| format!("{},{}", d * BURN_W / days, BURN_H - n as i64 * BURN_H / top as i64))

        .collect::<Vec<_>>()

        .join(" ");

    Ok(IterationView {

        first: day_of(it.start_ms),

        last: day_of(it.end_ms - 1),

        days,

        so_far: up.len(),

        done: times.len(),

        points,

        top,

        it,

    })

}

#[derive(Template)]

#[template(path = "project.html")]

pub struct BoardPage {

    shell: Shell,

    project: pdb::Project,

    columns: Vec<ColumnView>,

    /// The owner's repositories the viewer can read, for adding cards.

    repos: Vec<String>,

    /// Changes cards and columns (an open project).

    can_edit: bool,

    /// Changes the settings (to reopen a closed project too).

    can_manage: bool,

    notice: Option<String>,

    error: Option<String>,

    /// Owners the viewer may move the project to (#125): themselves and the

    /// organisations they belong to, but not its owner now.

    transfer_to: Vec<String>,

    /// The filter the page shows (#293), and whether one is set.

    q: String,

    state: String,

    filtered: bool,

    /// The archive view: archived cards, each restorable (#293).

    archived: bool,

    /// Archived cards on the whole board.

    archived_total: usize,

    /// The open iteration, the past ones (newest first), and the one the

    /// page shows the cards of (#343).

    current: Option<IterationView>,

    past: Vec<IterationView>,

    shown_iteration: Option<IterationView>,

    /// A new iteration's suggested first and last days: today and 13 days on.

    next_first: String,

    next_last: String,

}

#[allow(clippy::too_many_arguments)]

async fn board(

    app: &Shared,

    shell: Shell,

    viewer: &Viewer,

    owner: &str,

    number: i64,

    notice: Option<String>,

    error: Option<String>,

    view: &BoardQuery,

) -> Result<Page<BoardPage>, Error> {

    let e = |e| Error::from_db(shell.clone(), e);

    let r = rights(app, &shell, viewer, owner).await?;

    let project = pdb::get(&app.db, owner, number)

        .await

        .map_err(e)?

        .filter(|p| p.public || r.member)

        .ok_or_else(|| Error::not_found(shell.clone()))?;

    let now = db::now_ms();

    let iterations = pdb::iterations(&app.db, project.id).await.map_err(e)?;

    let shown = view.iteration.and_then(|id| iterations.iter().find(|i| i.id == id && i.closed_ms.is_some()).cloned());

    // A past iteration's page is the archive of what was done in it.

    let archived = view.archived() || shown.is_some();

    let (mut columns, repos) = board_columns(app, viewer.account(), owner, &project, archived).await.map_err(e)?;

    if let Some(it) = &shown {

        for col in columns.iter_mut() {

            col.cards.retain(|c| c.card.iteration_id == Some(it.id));

        }

    }

    shape(&mut columns, view);

    let archived_total = columns.iter().map(|c| c.archived).sum();

    let done = pdb::done_column(&columns.iter().map(|c| c.column.clone()).collect::<Vec<_>>());

    let (mut current, mut past) = (None, Vec::new());

    for it in iterations {

        if it.closed_ms.is_none() {

            current = Some(iteration_view(app, it, done, now).await.map_err(e)?);

        } else if past.len() < PAST_SHOWN {

            past.push(iteration_view(app, it, done, now).await.map_err(e)?);

        }

    }

    let shown_iteration = match shown {

        Some(it) => Some(iteration_view(app, it, done, now).await.map_err(e)?),

        None => None,

    };

    let can_edit = r.edit && !project.closed;

    let mut transfer_to = Vec::new();

    if let (true, Some(a)) = (r.edit, viewer.account()) {

        transfer_to.push(a.username.clone());

        let orgs = db::accounts::orgs_of(&app.db, a.id).await.map_err(e)?;

        transfer_to.extend(orgs.into_iter().map(|(o, _)| o.name));

        transfer_to.retain(|o| o != owner);

    }

    let (q, state) = (view.text(), view.state());

    let filtered = !q.is_empty() || !state.is_empty();

    Ok(Page(BoardPage {

        shell,

        project,

        columns,

        repos,

        can_edit,

        can_manage: r.edit,

        notice,

        error,

        transfer_to,

        q,

        state,

        filtered,

        archived,

        archived_total,

        current,

        past,

        shown_iteration,

        next_first: day_of(now),

        next_last: day_of(now + 13 * DAY_MS),

    }))

}

/// A project's columns with the cards `account` may see, and the owner's

/// repositories it can read (for adding cards). `archived`: the archived

/// cards instead of those on the board (#293); each column counts its

/// archived cards either way.

pub async fn board_columns(

    app: &Shared,

    account: Option<&db::accounts::Account>,

    owner: &str,

    project: &pdb::Project,

    archived: bool,

) -> sqlx::Result<(Vec<ColumnView>, Vec<String>)> {

    let mut readable: std::collections::HashMap<i64, db::repos::RepoRow> = Default::default();

    for row in db::repos::list_by_owner(&app.db, owner).await? {

        let role = roles::role_for(&app.db, account, &row).await?;

        if roles::allows(role, Access::Read) {

            readable.insert(row.id, row);

        }

    }

    let all = pdb::cards(&app.db, project.id).await?;

    let archived_in = |column: i64| all.iter().filter(|c| c.column_id == column && c.archived_ms.is_some()).count();

    let cards: Vec<&pdb::Card> = all.iter().filter(|c| c.archived_ms.is_some() == archived).collect();

    // What the cards show, read once per repository, not per card: a

    // board of 300 cards made 300 queries.

    let mut shown: std::collections::HashMap<(i64, bool, i64), Shown> = Default::default();

    let mut repo_ids: Vec<(i64, bool)> =

        cards.iter().filter_map(|c| Some((c.repo_id?, c.kind == "issue"))).filter(|(rid, _)| readable.contains_key(rid)).collect();

    repo_ids.sort();