//! A group at a glance: what is coming in each tool, and what is left to vote.
//!
//! What is coming is data, not code: `seeds/upcoming/<group>.json`, one file
//! per group, read once at start (titles in fr, en and es). It is served with
//! the group (`GET /api/groups/{slug}`, field `upcoming`), only to those who
//! open it. What is left to vote (`GET /api/groups/{slug}/decisions`) is one
//! line per document, counted by `ld_engine::pending`.

use crate::AppState;
use crate::auth::User;
use crate::docs;
use crate::error::AppResult;
use crate::util::{self, LangMap};
use anyhow::{Context, bail};
use axum::Json;
use axum::extract::{Path, State};
use ld_engine::pending::{Module, pending};
use serde::{Deserialize, Serialize};
use serde_json::{Value, json};
use std::collections::{BTreeMap, HashSet};

/// Something announced in a tool of a group, not open yet.
#[derive(Clone, Debug, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct UpcomingItem {
    pub key: String,
    pub title: LangMap,
}

/// What is coming in the tools of one group.
#[derive(Clone, Debug, Default, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct GroupUpcoming {
    #[serde(default)]
    pub docs: Vec<UpcomingItem>,
    #[serde(default)]
    pub mandats: Vec<UpcomingItem>,
    #[serde(default)]
    pub protocoles: Vec<UpcomingItem>,
}

impl GroupUpcoming {
    fn check(&self) -> anyhow::Result<()> {
        for (tool, items) in [("docs", &self.docs), ("mandats", &self.mandats), ("protocoles", &self.protocoles)] {
            let mut keys = HashSet::new();
            for item in items {
                if item.key.trim().is_empty() || !keys.insert(item.key.as_str()) {
                    bail!("{tool}: empty or repeated key « {} »", item.key);
                }
                for lang in util::LANGS {
                    if item.title.get(lang).is_none_or(|t| t.trim().is_empty()) {
                        bail!("{tool}/{}: no title in {lang}", item.key);
                    }
                }
            }
        }
        Ok(())
    }
}

/// Every group's announcements, by group slug.
#[derive(Clone, Debug, Default)]
pub struct Upcoming(BTreeMap<String, GroupUpcoming>);

impl Upcoming {
    /// Reads `<seed_dir>/upcoming/*.json`; no directory, nothing coming. A file
    /// that does not read, or lacks a language, stops the start.
    pub async fn load(seed_dir: &std::path::Path) -> anyhow::Result<Self> {
        let dir = seed_dir.join("upcoming");
        let mut entries = match tokio::fs::read_dir(&dir).await {
            Ok(e) => e,
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(Self::default()),
            Err(e) => return Err(e).context(dir.display().to_string()),
        };
        let mut out = BTreeMap::new();
        while let Some(entry) = entries.next_entry().await? {
            let path = entry.path();
            if path.extension().is_none_or(|x| x != "json") {
                continue;
            }
            let Some(group) = path.file_stem().and_then(|s| s.to_str()).map(str::to_owned) else { continue };
            let raw = tokio::fs::read_to_string(&path).await?;
            let parsed: GroupUpcoming = serde_json::from_str(&raw).with_context(|| path.display().to_string())?;
            parsed.check().with_context(|| path.display().to_string())?;
            out.insert(group, parsed);
        }
        Ok(Self(out))
    }

    pub fn of(&self, group: &str) -> GroupUpcoming {
        self.0.get(group).cloned().unwrap_or_default()
    }
}

/// The group, its tools and documents (`docs::group`), plus what is coming.
pub async fn group(State(state): State<AppState>, user: User, Path(slug): Path<String>) -> AppResult<Json<Value>> {
    let Json(mut view) = docs::group(State(state.clone()), user, Path(slug.clone())).await?;
    let open = view["group"]["open"].as_bool().unwrap_or(false);
    let upcoming = if open { state.upcoming.of(&slug) } else { GroupUpcoming::default() };
    view["upcoming"] = serde_json::to_value(upcoming).unwrap_or(Value::Null);
    Ok(Json(view))
}

/// « Décisions »: one line per document in progress, with its modules left to vote.
pub async fn decisions(
    State(state): State<AppState>,
    User(user): User,
    Path(slug): Path<String>,
) -> AppResult<Json<Value>> {
    let group = docs::load_group(&state, &slug).await?;
    docs::require_open(&state, &user, &group).await?;
    let can_vote = crate::ballots::access(&state, &user, &group).await?["open"].as_bool().unwrap_or(false);
    #[derive(sqlx::FromRow)]
    struct DocRow {
        id: String,
        slug: String,
        title: String,
    }
    let rows =
        sqlx::query_as::<_, DocRow>("SELECT id, slug, title FROM documents WHERE group_slug = ? ORDER BY created_at")
            .bind(&slug)
            .fetch_all(&state.db)
            .await?;
    let mut out = Vec::with_capacity(rows.len());
    for d in rows {
        let p = pending(&modules(&state, &d.id, &user.id).await?);
        out.push(json!({
            "id": d.id, "slug": d.slug, "title": util::parse_lang(&d.title),
            "toVote": p.to_vote,
            "withoutMyVote": can_vote.then_some(p.without_my_vote),
        }));
    }
    Ok(Json(json!({ "canVote": can_vote, "docs": out })))
}

/// The modules of a document as `me` sees them — its articles, its title, the
/// order of each section (ADR 0009): the version in force (adopted by a vote,
/// or a seed a minima), the open versions, and whether `me` holds a valid vote
/// on one of them. A change of inertia is not a version of the text; the order
/// of a section of fewer than two articles has nothing to decide; a version held
/// by an objection is nobody's to vote while it is held (ADR 0010).
async fn modules(state: &AppState, doc_id: &str, me: &str) -> AppResult<Vec<Module>> {
    #[derive(sqlx::FromRow)]
    struct VersionRow {
        id: String,
        unit_id: String,
        in_force: bool,
        adopted: bool,
        voted: bool,
    }
    let st = docs::load_state(state, doc_id).await?;
    let moot: HashSet<String> = st
        .modules(crate::modules::ModuleKind::Order)
        .into_iter()
        .filter(|u| ld_engine::order::is_moot(&st.members(u.section.as_deref().unwrap_or_default())))
        .map(|u| u.id.clone())
        .collect();
    let rows = sqlx::query_as::<_, VersionRow>(
        "SELECT p.id AS id, u.id AS unit_id,
                IFNULL(p.id = u.in_force_id, 0) AS in_force,
                (p.entered_at IS NOT NULL OR p.confirmed_at IS NOT NULL OR p.origin <> 'seed') AS adopted,
                EXISTS (SELECT 1 FROM votes v
                         WHERE v.proposal_id = p.id AND v.revision = p.revision
                           AND (v.identity_id = ?1 OR v.ballot_id IN
                                (SELECT b.id FROM ballots b WHERE b.requested_by = ?1 AND b.status = 'confirmed'))) AS voted
           FROM units u JOIN proposals p ON p.unit_id = u.id
          WHERE u.doc_id = ?2 AND p.kind <> 'inertia' AND (p.id = u.in_force_id OR p.status = 'open')
          ORDER BY u.position, u.id",
    )
    .bind(me)
    .bind(doc_id)
    .fetch_all(&state.db)
    .await?;
    let mut out: Vec<Module> = Vec::new();
    let mut current: Option<String> = None;
    for r in rows {
        if current.as_deref() != Some(r.unit_id.as_str()) {
            out.push(Module { moot: moot.contains(&r.unit_id), ..Module::default() });
            current = Some(r.unit_id);
        }
        if let Some(m) = out.last_mut() {
            if r.in_force {
                m.in_force = Some(r.adopted);
            } else if st.proposals.iter().any(|p| p.id == r.id && st.votable(p)) {
                m.open += 1;
            }
            m.voted |= r.voted;
        }
    }
    Ok(out)
}

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

    async fn load(files: &[(&str, &str)]) -> anyhow::Result<Upcoming> {
        let dir = std::env::temp_dir().join(format!("ld-upcoming-{}", util::id()));
        tokio::fs::create_dir_all(dir.join("upcoming")).await?;
        for (name, body) in files {
            tokio::fs::write(dir.join("upcoming").join(name), body).await?;
        }
        let out = Upcoming::load(&dir).await;
        let _ = tokio::fs::remove_dir_all(&dir).await;
        out
    }

    const ITEM: &str = r#"{"key": "k", "title": {"fr": "Un", "en": "One", "es": "Uno"}}"#;

    #[tokio::test]
    async fn one_file_per_group_and_nothing_elsewhere() {
        let up =
            load(&[("axiom.json", &format!(r#"{{"mandats": [{ITEM}]}}"#)), ("notes.txt", "x")]).await.expect("load");
        assert_eq!(up.of("axiom").mandats.len(), 1);
        assert!(up.of("axiom").docs.is_empty());
        assert!(up.of("librodrome").mandats.is_empty());
        let none = Upcoming::load(&std::env::temp_dir().join("ld-no-such-dir")).await.expect("load");
        assert!(none.of("axiom").docs.is_empty());
    }

    #[tokio::test]
    async fn a_missing_language_an_unknown_tool_or_a_repeated_key_stops_the_start() {
        let no_es = r#"{"docs": [{"key": "k", "title": {"fr": "Un", "en": "One"}}]}"#;
        assert!(load(&[("axiom.json", no_es)]).await.is_err());
        assert!(load(&[("axiom.json", &format!(r#"{{"outils": [{ITEM}]}}"#))]).await.is_err());
        assert!(load(&[("axiom.json", &format!(r#"{{"docs": [{ITEM}, {ITEM}]}}"#))]).await.is_err());
    }

    #[tokio::test]
    async fn the_seeds_of_the_repository_read() {
        let up = Upcoming::load(&Config::for_tests().seed_dir).await.expect("load");
        assert_eq!(up.of("monnaie-libre").mandats.len(), 2);
    }
}