//! Quorum amendments — the quorums by level a seed now gives a document, written into
//! a document born without them (ADR 0013).
//!
//! Yvv, 2026-11-02: « 12 · 12 · 50 · 50 · 50 » in Monnaie libre, the test group at 1
//! everywhere. A new base gets them from the seed (`quorums` of each instance). An
//! existing base — production holds two instances of the certification act — reads
//! `vote_floor` at every level until then (the C of before: 50 and 1), and gets them
//! through an amendment listed here: written **only where the document holds none**;
//! nothing else is touched (no article's own quorum, no vote, no text).
//!
//! Like the other amendments of the seed, each document is decided once, at the first
//! start that knows the amendment, and the decision is kept in `quorum_amendments`
//! (applied, refused and why, or present) and in the logs. Applied where the document
//! publishes, the publication queue gets a row (`document.json` carries the quorums).

use crate::AppState;
use crate::seed::{SeedDoc, quorums_json};
use crate::util;

/// The quorums by level to write into every document instantiated from a seed.
pub struct QuorumAmendment {
    /// Stable identifier: each document's decision is kept under it.
    pub id: &'static str,
    /// Slug of the seed document.
    pub doc: &'static str,
    /// The quorums of each group's instance: the seed's today, which must say so.
    pub quorums: &'static [(&'static str, [u32; 5])],
    /// Reason given to the publication queue, and so to the commit of the texts.
    pub reason: &'static str,
}

pub const AMENDMENTS: &[QuorumAmendment] = &[QuorumAmendment {
    id: "2026-11-03-quorums-par-cran",
    doc: "acte-engagement-certification",
    quorums: &[("monnaie-libre", [12, 12, 50, 50, 50]), ("essai", [1, 1, 1, 1, 1])],
    reason: "quorums par cran : 12 · 12 · 50 · 50 · 50 (ADR 0013)",
}];

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Verdict {
    Apply,
    /// Born with these quorums: nothing to do.
    Present,
    Refuse(&'static str),
}

/// The rule, apart from the database: `found` is what the document holds.
pub fn verdict(found: Option<&str>, wanted: &[u32; 5]) -> Verdict {
    match found {
        None => Verdict::Apply,
        Some(raw) if serde_json::from_str::<[u32; 5]>(raw).ok().as_ref() == Some(wanted) => Verdict::Present,
        // Written otherwise: kept as it is.
        Some(_) => Verdict::Refuse("quorums_set"),
    }
}

/// A decision taken at this start.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Outcome {
    pub amendment: &'static str,
    pub group: String,
    pub verdict: Verdict,
}

/// Decides every amendment not yet decided, document by document.
pub async fn apply(state: &AppState, seeds: &[SeedDoc], list: &[QuorumAmendment]) -> anyhow::Result<Vec<Outcome>> {
    let mut out = Vec::new();
    for a in list {
        let docs: Vec<(String, String, Option<String>)> =
            sqlx::query_as("SELECT id, group_slug, publish_path FROM documents WHERE slug = ? ORDER BY group_slug")
                .bind(a.doc)
                .fetch_all(&state.db)
                .await?;
        for (doc_id, group, publish_path) in docs {
            let Some(wanted) = seed_says(seeds, a, &group) else { continue };
            let Some(v) = decide(state, a, &wanted, &doc_id, publish_path.is_some()).await? else { continue };
            match v {
                Verdict::Apply => tracing::info!(amendment = a.id, %group, quorums = ?wanted, "quorums written"),
                Verdict::Present => tracing::info!(amendment = a.id, %group, "quorums: already there"),
                Verdict::Refuse(why) => {
                    tracing::warn!(amendment = a.id, %group, reason = why, "quorums refused: the document keeps its own")
                }
            }
            if v == Verdict::Apply && publish_path.is_some() {
                state.publish_wake.notify_one();
            }
            out.push(Outcome { amendment: a.id, group, verdict: v });
        }
    }
    Ok(out)
}

/// The seed must give the group's instance the quorums the amendment writes: a seed
/// edited later never reaches a base by this way, and a seed without them decides nothing.
fn seed_says(seeds: &[SeedDoc], a: &QuorumAmendment, group: &str) -> Option<[u32; 5]> {
    let wanted = a.quorums.iter().find(|(g, _)| *g == group).map(|(_, q)| *q)?;
    let declared = seeds
        .iter()
        .find(|s| s.slug == a.doc)
        .and_then(|s| s.instances.iter().find(|i| i.group == group))
        .and_then(|i| i.quorums);
    if declared == Some(wanted) {
        Some(wanted)
    } else {
        tracing::warn!(amendment = a.id, doc = a.doc, %group, "quorum amendment: the seed does not give these quorums, nothing decided");
        None
    }
}

/// One document, in one transaction: `None` when it was decided at an earlier start.
async fn decide(
    state: &AppState,
    a: &QuorumAmendment,
    wanted: &[u32; 5],
    doc_id: &str,
    publishes: bool,
) -> anyhow::Result<Option<Verdict>> {
    let mut tx = state.db.begin().await?;
    let decided: i64 =
        sqlx::query_scalar("SELECT COUNT(*) FROM quorum_amendments WHERE amendment_id = ? AND doc_id = ?")
            .bind(a.id)
            .bind(doc_id)
            .fetch_one(&mut *tx)
            .await?;
    if decided > 0 {
        return Ok(None);
    }
    let found: Option<String> =
        sqlx::query_scalar("SELECT quorums FROM documents WHERE id = ?").bind(doc_id).fetch_one(&mut *tx).await?;
    let v = verdict(found.as_deref(), wanted);
    let now = util::now();
    let to = quorums_json(wanted);
    if v == Verdict::Apply {
        sqlx::query("UPDATE documents SET quorums = ? WHERE id = ? AND quorums IS NULL")
            .bind(&to)
            .bind(doc_id)
            .execute(&mut *tx)
            .await?;
        if publishes {
            sqlx::query("INSERT INTO outbox (doc_id, reason, created_at, next_at) VALUES (?, ?, ?, ?)")
                .bind(doc_id)
                .bind(a.reason)
                .bind(&now)
                .bind(&now)
                .execute(&mut *tx)
                .await?;
        }
    }
    let (outcome, reason) = match v {
        Verdict::Apply => ("applied", None),
        Verdict::Present => ("present", None),
        Verdict::Refuse(why) => ("refused", Some(why)),
    };
    sqlx::query(
        "INSERT INTO quorum_amendments (amendment_id, doc_id, from_quorums, to_quorums, outcome, reason, at)
         VALUES (?, ?, ?, ?, ?, ?, ?)",
    )
    .bind(a.id)
    .bind(doc_id)
    .bind(&found)
    .bind(&to)
    .bind(outcome)
    .bind(reason)
    .bind(&now)
    .execute(&mut *tx)
    .await?;
    tx.commit().await?;
    Ok(Some(v))
}

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

    const ML: [u32; 5] = [12, 12, 50, 50, 50];

    #[test]
    fn written_where_none_kept_where_other() {
        assert_eq!(verdict(None, &ML), Verdict::Apply);
        assert_eq!(verdict(Some("[12,12,50,50,50]"), &ML), Verdict::Present);
        assert_eq!(verdict(Some("[12, 12, 50, 50, 50]"), &ML), Verdict::Present, "the same numbers");
        assert_eq!(verdict(Some("[3,3,3,3,3]"), &ML), Verdict::Refuse("quorums_set"));
        assert_eq!(verdict(Some("not json"), &ML), Verdict::Refuse("quorums_set"));
    }

    #[test]
    fn the_amendment_says_what_the_seed_says() {
        let seed: serde_json::Value =
            serde_json::from_str(include_str!("../../../seeds/acte-engagement-certification.json")).expect("seed");
        for (group, quorums) in AMENDMENTS[0].quorums {
            let inst = seed["instances"].as_array().expect("instances").iter().find(|i| i["group"] == *group);
            assert_eq!(inst.map(|i| i["quorums"].clone()), Some(serde_json::json!(quorums)), "{group}");
        }
    }
}