use reqwest::Client;
use sqlx::PgPool;
use tracing::{info, warn};

/// Oppvarming: les siste N meldinger per aktive kanal fra PG og last inn i SpacetimeDB.
pub async fn run(
    pool: &PgPool,
    http: &Client,
    spacetimedb_url: &str,
    module: &str,
    limit: i64,
) -> anyhow::Result<()> {
    info!(limit, "Starter oppvarming (PG → SpacetimeDB)");

    // Finn aktive kanaler (kanaler med meldinger)
    let channels: Vec<(String,)> = sqlx::query_as(
        "SELECT DISTINCT channel_id::text FROM messages WHERE channel_id IS NOT NULL"
    )
    .fetch_all(pool)
    .await?;

    if channels.is_empty() {
        info!("Ingen aktive kanaler funnet — oppvarming fullført");
        return Ok(());
    }

    info!(channels = channels.len(), "Aktive kanaler funnet");

    let mut total_messages = 0u64;
    let mut total_reactions = 0u64;

    for (channel_id,) in &channels {
        // Rydd kanalen i SpacetimeDB først for å unngå duplikater
        if let Err(e) = call_reducer(http, spacetimedb_url, module, "clear_channel", &serde_json::json!({
            "channel_id": channel_id
        })).await {
            warn!(channel_id, error = %e, "Kunne ikke rydde kanal — hopper over");
            continue;
        }

        // Hent meldinger med forfatterinfo
        let rows: Vec<(String, String, String, String, String, String, String, Option<String>, String)> = sqlx::query_as(
            r#"
            SELECT
                m.id::text,
                m.channel_id::text,
                n.workspace_id::text,
                COALESCE(m.author_id, ''),
                COALESCE(u.name, 'Ukjent'),
                COALESCE(m.body, ''),
                COALESCE(m.message_type, 'text'),
                m.reply_to::text,
                m.created_at::text
            FROM messages m
            JOIN nodes n ON n.id = m.id
            LEFT JOIN users u ON u.authentik_id = m.author_id
            WHERE m.channel_id = $1::uuid
            ORDER BY m.created_at DESC
            LIMIT $2
            "#
        )
        .bind(channel_id)
        .bind(limit)
        .fetch_all(pool)
        .await?;

        if rows.is_empty() { continue; }

        // Bygg JSON-array
        let messages: Vec<serde_json::Value> = rows.iter().map(|r| {
            serde_json::json!({
                "id": r.0,
                "channel_id": r.1,
                "workspace_id": r.2,
                "author_id": r.3,
                "author_name": r.4,
                "body": r.5,
                "message_type": r.6,
                "reply_to": r.7.as_deref().unwrap_or(""),
                "created_at": r.8
            })
        }).collect();

        let count = messages.len();
        let json_str = serde_json::to_string(&messages)?;

        if let Err(e) = call_reducer(http, spacetimedb_url, module, "load_messages", &serde_json::json!({
            "messages_json": json_str
        })).await {
            warn!(channel_id, error = %e, "Feil ved lasting av meldinger");
            continue;
        }

        total_messages += count as u64;

        // Hent reaksjoner for denne kanalens meldinger
        let reaction_rows: Vec<(String, String, String, String)> = sqlx::query_as(
            r#"
            SELECT
                mr.message_id::text,
                COALESCE(mr.user_id, ''),
                COALESCE(u.name, 'Ukjent'),
                mr.reaction
            FROM message_reactions mr
            JOIN messages m ON m.id = mr.message_id
            LEFT JOIN users u ON u.authentik_id = mr.user_id
            WHERE m.channel_id = $1::uuid
            "#
        )
        .bind(channel_id)
        .fetch_all(pool)
        .await?;

        if !reaction_rows.is_empty() {
            let reactions: Vec<serde_json::Value> = reaction_rows.iter().map(|r| {
                serde_json::json!({
                    "message_id": r.0,
                    "user_id": r.1,
                    "user_name": r.2,
                    "reaction": r.3
                })
            }).collect();

            let reactions_json = serde_json::to_string(&reactions)?;
            if let Err(e) = call_reducer(http, spacetimedb_url, module, "load_reactions", &serde_json::json!({
                "reactions_json": reactions_json
            })).await {
                warn!(channel_id, error = %e, "Feil ved lasting av reaksjoner");
            } else {
                total_reactions += reaction_rows.len() as u64;
            }
        }

        info!(channel_id, messages = count, reactions = reaction_rows.len(), "Kanal oppvarmet");
    }

    info!(
        channels = channels.len(),
        messages = total_messages,
        reactions = total_reactions,
        "Oppvarming fullført"
    );

    Ok(())
}

async fn call_reducer(
    http: &Client,
    base_url: &str,
    module: &str,
    reducer: &str,
    args: &serde_json::Value,
) -> anyhow::Result<()> {
    let url = format!("{}/v1/database/{}/call/{}", base_url, module, reducer);
    let resp = http
        .post(&url)
        .json(args)
        .send()
        .await?;

    if !resp.status().is_success() {
        let status = resp.status();
        let body = resp.text().await.unwrap_or_default();
        anyhow::bail!("{} feilet ({}): {}", reducer, status, body);
    }

    Ok(())
}