//! Project-root discovery, subsystem initialisation (log, identity, DB, CRDT),
//! and CRDT-sync configuration.

use crate::config;
use crate::crdt_state;
use crate::crdt_sync;
use crate::db;
use crate::io::fs::find_story_kit_root;
use crate::log_buffer;
use crate::node_identity;
use crate::state::SessionState;
use crate::store::JsonFileStore;
use crate::worktree;
use std::path::{Path, PathBuf};
use std::sync::Arc;

/// Open (or scaffold) the project root according to the CLI flags and CWD.
///
/// Handles `--init`, an explicit path argument, and the default auto-detect
/// behaviour.  Modifies `app_state.project_root` as a side effect.
pub(crate) async fn open_project_root(
    is_init: bool,
    explicit_path: Option<PathBuf>,
    cwd: &Path,
    app_state: &Arc<SessionState>,
    store: &Arc<JsonFileStore>,
    port: u16,
) {
    if is_init {
        let init_root = explicit_path.unwrap_or_else(|| cwd.to_path_buf());
        if !init_root.exists() {
            std::fs::create_dir_all(&init_root).unwrap_or_else(|e| {
                eprintln!(
                    "error: cannot create directory {}: {e}",
                    init_root.display()
                );
                std::process::exit(1);
            });
        }
        match crate::io::fs::open_project(
            init_root.to_string_lossy().to_string(),
            app_state,
            store.as_ref(),
            port,
        )
        .await
        {
            Ok(_) => {
                if let Some(root) = app_state.project_root.lock().unwrap().as_ref() {
                    config::ProjectConfig::load(root)
                        .unwrap_or_else(|e| panic!("Invalid project.toml: {e}"));
                    crate::io::wizard::WizardState::init_if_missing(root);
                }
            }
            Err(e) => {
                eprintln!("error: {e}");
                std::process::exit(1);
            }
        }
    } else if let Some(explicit_root) = explicit_path {
        match crate::io::fs::open_project(
            explicit_root.to_string_lossy().to_string(),
            app_state,
            store.as_ref(),
            port,
        )
        .await
        {
            Ok(_) => {
                if let Some(root) = app_state.project_root.lock().unwrap().as_ref() {
                    config::ProjectConfig::load(root)
                        .unwrap_or_else(|e| panic!("Invalid project.toml: {e}"));
                }
            }
            Err(e) => {
                eprintln!("error: {e}");
                std::process::exit(1);
            }
        }
    } else if let Some(project_root) = find_story_kit_root(cwd) {
        crate::io::fs::open_project(
            project_root.to_string_lossy().to_string(),
            app_state,
            store.as_ref(),
            port,
        )
        .await
        .unwrap_or_else(|e| {
            crate::slog!("Warning: failed to auto-open project at {project_root:?}: {e}");
            project_root.to_string_lossy().to_string()
        });

        config::ProjectConfig::load(&project_root)
            .unwrap_or_else(|e| panic!("Invalid project.toml: {e}"));
    } else {
        crate::io::fs::open_project(
            cwd.to_string_lossy().to_string(),
            app_state,
            store.as_ref(),
            port,
        )
        .await
        .unwrap_or_else(|e| {
            crate::slog!("Warning: failed to scaffold project at {cwd:?}: {e}");
            cwd.to_string_lossy().to_string()
        });
    }
}

/// One-shot migration: read existing JSON store files and insert their rows
/// into the SQLite tables created by the migration scripts, then rename the
/// originals to `*.migrated` so this function is a no-op on the next startup.
///
/// Runs after `db::init()` so the tables already exist and the shared pool is
/// available.  Errors are logged but never fatal.
async fn migrate_json_stores_to_sqlite(huskies_dir: &Path) {
    let pool = match crate::db::get_shared_pool() {
        Some(p) => p,
        None => {
            crate::slog!("[db-migrate] Shared pool not available; skipping JSON migration");
            return;
        }
    };

    // ── event_triggers.json ───────────────────────────────────────────────────
    let et_path = huskies_dir.join("event_triggers.json");
    if et_path.exists() {
        match std::fs::read_to_string(&et_path) {
            Ok(s) => {
                let triggers: Vec<crate::service::event_triggers::EventTrigger> =
                    serde_json::from_str(&s).unwrap_or_default();
                for t in triggers {
                    let predicate_json = serde_json::to_string(&t.predicate).unwrap_or_default();
                    let action_json = serde_json::to_string(&t.action).unwrap_or_default();
                    let mode = match t.mode {
                        crate::service::event_triggers::FireMode::Once => "once",
                        crate::service::event_triggers::FireMode::Persistent => "persistent",
                    };
                    let created_at = t.created_at.to_rfc3339();
                    let _ = sqlx::query(
                        "INSERT OR IGNORE INTO event_triggers \
                         (id, predicate_json, action_json, mode, created_at) \
                         VALUES (?1, ?2, ?3, ?4, ?5)",
                    )
                    .bind(&t.id)
                    .bind(&predicate_json)
                    .bind(&action_json)
                    .bind(mode)
                    .bind(&created_at)
                    .execute(pool)
                    .await;
                }
                let migrated = huskies_dir.join("event_triggers.json.migrated");
                let _ = std::fs::rename(&et_path, &migrated);
                crate::slog!("[db-migrate] Migrated event_triggers.json → SQLite");
            }
            Err(e) => crate::slog!("[db-migrate] Could not read event_triggers.json: {e}"),
        }
    }

    // ── timers.json ───────────────────────────────────────────────────────────
    let timers_path = huskies_dir.join("timers.json");
    if timers_path.exists() {
        match std::fs::read_to_string(&timers_path) {
            Ok(s) => {
                let entries: Vec<crate::service::timer::TimerEntry> =
                    serde_json::from_str(&s).unwrap_or_default();
                for e in entries {
                    let _ = sqlx::query(
                        "INSERT OR IGNORE INTO timers (story_id, scheduled_at) \
                         VALUES (?1, ?2)",
                    )
                    .bind(&e.story_id)
                    .bind(e.scheduled_at.to_rfc3339())
                    .execute(pool)
                    .await;
                }
                let migrated = huskies_dir.join("timers.json.migrated");
                let _ = std::fs::rename(&timers_path, &migrated);
                crate::slog!("[db-migrate] Migrated timers.json → SQLite");
            }
            Err(e) => crate::slog!("[db-migrate] Could not read timers.json: {e}"),
        }
    }

    // ── scheduled_timers.json ─────────────────────────────────────────────────
    let st_path = huskies_dir.join("scheduled_timers.json");
    if st_path.exists() {
        match std::fs::read_to_string(&st_path) {
            Ok(s) => {
                use crate::service::timer::scheduled::ScheduledTimer;
                let entries: Vec<ScheduledTimer> = serde_json::from_str(&s).unwrap_or_default();
                for t in entries {
                    let action_json = serde_json::to_string(&t.action).unwrap_or_default();
                    let mode_json = serde_json::to_string(&t.mode).unwrap_or_default();
                    let _ = sqlx::query(
                        "INSERT OR IGNORE INTO scheduled_timers \
                         (id, label, fire_at, action_json, mode_json, created_at) \
                         VALUES (?1, ?2, ?3, ?4, ?5, ?6)",
                    )
                    .bind(&t.id)
                    .bind(&t.label)
                    .bind(t.fire_at.to_rfc3339())
                    .bind(&action_json)
                    .bind(&mode_json)
                    .bind(t.created_at.to_rfc3339())
                    .execute(pool)
                    .await;
                }
                let migrated = huskies_dir.join("scheduled_timers.json.migrated");
                let _ = std::fs::rename(&st_path, &migrated);
                crate::slog!("[db-migrate] Migrated scheduled_timers.json → SQLite");
            }
            Err(e) => crate::slog!("[db-migrate] Could not read scheduled_timers.json: {e}"),
        }
    }
}

/// Set up the server log file, node identity keypair, pipeline DB, and CRDT state.
///
/// When `is_agent` is `true` the pipeline database is opened at an isolated
/// temporary path (or at `HUSKIES_DB_PATH` if that env-var is set) so that the
/// headless build agent never touches the production `.huskies/pipeline.db`.
/// This prevents feature-branch migrations from being applied to the shared
/// database and bricking the next server restart.
pub(crate) async fn init_subsystems(app_state: &Arc<SessionState>, cwd: &Path, is_agent: bool) {
    // Enable persistent server log file now that the project root is known.
    if let Some(ref root) = *app_state.project_root.lock().unwrap() {
        let log_dir = root.join(".huskies").join("logs");
        let _ = std::fs::create_dir_all(&log_dir);
        log_buffer::global().set_log_dir(log_dir);
    }

    // Initialise the node's Ed25519 identity keypair (file-based, mode 0600).
    // The key is stored at .huskies/node_identity.key and persisted across restarts.
    {
        let key_path = app_state
            .project_root
            .lock()
            .unwrap()
            .as_ref()
            .map(|root| root.join(".huskies").join("node_identity.key"))
            .unwrap_or_else(|| cwd.join(".huskies").join("node_identity.key"));
        if let Err(e) = node_identity::init_identity(&key_path) {
            crate::slog!("[identity] Failed to initialise node identity keypair: {e}");
        } else if let Some(id) = node_identity::get_identity() {
            crate::slog!("[identity] Node ID: {}", id.node_id);
        }
    }

    // Resolve the pipeline DB path.
    //
    // Priority order:
    //   1. HUSKIES_DB_PATH env var (operator override, any mode)
    //   2. Agent mode: process-local temp file so the production DB is never touched
    //   3. Default: {project_root}/.huskies/pipeline.db
    let pipeline_db_path: Option<PathBuf> = if let Ok(env_path) = std::env::var("HUSKIES_DB_PATH") {
        let p = PathBuf::from(&env_path);
        crate::slog!("[db] HUSKIES_DB_PATH override: {}", p.display());
        Some(p)
    } else if is_agent {
        // Headless agent: use an isolated temp DB so that any migrations compiled
        // into this binary (e.g. from a feature branch) are never applied to the
        // production database.  The temp file is process-unique and harmless to
        // leave behind after the agent exits.
        let pid = std::process::id();
        let temp_path = std::env::temp_dir().join(format!("huskies-agent-{pid}.db"));
        crate::slog!(
            "[db] Agent mode: using isolated DB at {} (not touching production pipeline.db)",
            temp_path.display()
        );
        Some(temp_path)
    } else {
        // Server mode: use the project-local production database.
        app_state
            .project_root
            .lock()
            .unwrap()
            .as_ref()
            .map(|root| root.join(".huskies").join("pipeline.db"))
    };

    if let Some(ref db_path) = pipeline_db_path {
        if let Err(e) = db::init(db_path).await {
            crate::slog!("[db] Failed to initialise pipeline.db: {e}");
        } else {
            // ── Migration drift self-check (server mode only) ─────────────────────
            //
            // In server mode, detect whether the live database contains migrations
            // that were applied by a newer binary (e.g. a feature-branch agent that
            // ran before the feature was merged).  If so, log each unknown migration
            // and exit with a clear actionable message.  This is the root cause of
            // the 2026-05-14 21:07 production outage where the server came up but
            // the CRDT never initialised.
            if !is_agent && let Some(pool) = db::get_shared_pool() {
                let drift = db::check_schema_drift(pool).await;
                if !drift.is_empty() {
                    for m in &drift {
                        crate::slog!(
                            "[db] UNKNOWN migration {} ('{}') applied at {} \
                             is not in the compiled-in set",
                            m.version,
                            m.description,
                            m.installed_on,
                        );
                    }
                    eprintln!();
                    eprintln!(
                        "error: pipeline.db contains {} migration(s) that are not \
                         recognised by this binary:",
                        drift.len()
                    );
                    for m in &drift {
                        eprintln!(
                            "  \u{2022} migration {} ('{}') applied at {}",
                            m.version, m.description, m.installed_on
                        );
                    }
                    eprintln!();
                    eprintln!(
                        "This means the database was previously opened by a newer \
                         version of huskies."
                    );
                    eprintln!(
                        "To fix: rebuild huskies from the latest source (the branch \
                         that added these migrations) and restart."
                    );
                    eprintln!(
                        "Do NOT start the old binary against this database — it will \
                         behave incorrectly."
                    );
                    std::process::exit(1);
                }
            }

            // One-shot migration: move any existing JSON store files into SQLite.
            let huskies_dir = db_path.parent().unwrap_or(db_path);
            migrate_json_stores_to_sqlite(huskies_dir).await;
        }
        if let Err(e) = crdt_state::init(db_path).await {
            crate::slog!("[crdt] Failed to initialise CRDT state layer: {e}");
        } else {
            crdt_state::migrate_names_from_slugs();
            // Story 934 stage 6: rewrite any pre-934 directory-style stage
            // strings to the clean post-934 wire vocabulary, and set the new
            // `frozen` flag on items that were previously at `Stage::Frozen`.
            // Must run before legacy stage-string acceptance is dropped from
            // `Stage::from_dir` (also part of stage 6).
            crdt_state::migrate_legacy_stage_strings();
            let id_migrations = crdt_state::migrate_story_ids_to_numeric();
            if !id_migrations.is_empty()
                && let Some(project_root) = db_path.parent().and_then(|p| p.parent())
            {
                worktree::migrate_slug_paths(project_root, &id_migrations);
            }
            // Story 987: upgrade four-bool MergeJob entries to typed MergeResult enum.
            crdt_state::migrate_merge_job(db_path);
            // Story 1009: drop legacy node-hex claims that can't be converted to AgentName.
            crdt_state::migrate_node_claims_to_agent_claims();
            // Story 1052: remove stale MergeJob entries for terminal-stage
            // stories so they can never cause "FAILED" labels in the UI.
            crdt_state::purge_done_stage_merge_jobs();
            // Story 1094: delete pipeline_items rows whose CRDT entry is
            // tombstoned but whose row survived with a non-terminal stage
            // (pre-1094 fire-and-forget delete could be lost on restart).
            crdt_state::migrate_zombie_pipeline_rows().await;
        }
    }
}

/// Wire up CRDT sync: trusted keys, token auth, and the rendezvous client.
///
/// In agent mode the rendezvous URL comes from the CLI; otherwise it is read
/// from `project.toml`.
pub(crate) fn configure_crdt_sync(
    app_state: &Arc<SessionState>,
    is_agent: bool,
    agent_rendezvous: Option<String>,
    crdt_join_token: Option<String>,
) {
    let sync_config = if is_agent {
        agent_rendezvous
            .clone()
            .map(|url| (url, Vec::new(), false, Vec::new()))
    } else {
        app_state
            .project_root
            .lock()
            .unwrap()
            .as_ref()
            .and_then(|root| config::ProjectConfig::load(root).ok())
            .and_then(|cfg| {
                cfg.rendezvous.map(|url| {
                    (
                        url,
                        cfg.trusted_keys,
                        cfg.crdt_require_token,
                        cfg.crdt_tokens,
                    )
                })
            })
    };

    if let Some((rendezvous_url, trusted_keys, require_token, crdt_tokens)) = sync_config {
        crdt_sync::init_trusted_keys(trusted_keys);
        crdt_sync::init_token_auth(require_token, crdt_tokens);
        crdt_sync::spawn_rendezvous_client(rendezvous_url, crdt_join_token);
    } else {
        let (keys, require_token, crdt_tokens) = app_state
            .project_root
            .lock()
            .unwrap()
            .as_ref()
            .and_then(|root| config::ProjectConfig::load(root).ok())
            .map(|cfg| (cfg.trusted_keys, cfg.crdt_require_token, cfg.crdt_tokens))
            .unwrap_or_default();
        crdt_sync::init_trusted_keys(keys);
        crdt_sync::init_token_auth(require_token, crdt_tokens);
    }
}