"""SQLite database — schema, migrations, connection management."""

import json
import logging
import sqlite3
from contextlib import contextmanager

from . import config

logger = logging.getLogger("pipeline.db")

SCHEMA_VERSION = 3

SCHEMA_SQL = """
CREATE TABLE IF NOT EXISTS schema_version (
    version INTEGER PRIMARY KEY,
    applied_at TEXT DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS sources (
    path TEXT PRIMARY KEY,
    status TEXT NOT NULL DEFAULT 'unprocessed',
    -- unprocessed, triaging, extracting, extracted, null_result,
    -- needs_reextraction, error
    priority TEXT DEFAULT 'medium',
    -- critical, high, medium, low, skip
    priority_log TEXT DEFAULT '[]',
    -- JSON array: [{stage, priority, reasoning, ts}]
    extraction_model TEXT,
    claims_count INTEGER DEFAULT 0,
    pr_number INTEGER,
    transient_retries INTEGER DEFAULT 0,
    substantive_retries INTEGER DEFAULT 0,
    last_error TEXT,
    feedback TEXT,
    -- eval feedback for re-extraction (JSON)
    cost_usd REAL DEFAULT 0,
    created_at TEXT DEFAULT (datetime('now')),
    updated_at TEXT DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS prs (
    number INTEGER PRIMARY KEY,
    source_path TEXT REFERENCES sources(path),
    branch TEXT,
    status TEXT NOT NULL DEFAULT 'open',
    -- validating, open, reviewing, approved, merging, merged, closed, zombie, conflict
    -- conflict: rebase failed or merge timed out — needs human intervention
    domain TEXT,
    agent TEXT,
    tier TEXT,
    -- LIGHT, STANDARD, DEEP
    tier0_pass INTEGER,
    -- 0/1
    leo_verdict TEXT DEFAULT 'pending',
    -- pending, approve, request_changes, skipped, failed
    domain_verdict TEXT DEFAULT 'pending',
    domain_agent TEXT,
    domain_model TEXT,
    priority TEXT,
    -- NULL = inherit from source. Set explicitly for human-submitted PRs.
    -- Pipeline PRs: COALESCE(p.priority, s.priority, 'medium')
    -- Human PRs: 'critical' (detected via missing source_path or non-agent author)
    origin TEXT DEFAULT 'pipeline',
    -- pipeline | human | external
    transient_retries INTEGER DEFAULT 0,
    substantive_retries INTEGER DEFAULT 0,
    last_error TEXT,
    last_attempt TEXT,
    cost_usd REAL DEFAULT 0,
    created_at TEXT DEFAULT (datetime('now')),
    merged_at TEXT
);

CREATE TABLE IF NOT EXISTS costs (
    date TEXT,
    model TEXT,
    stage TEXT,
    calls INTEGER DEFAULT 0,
    input_tokens INTEGER DEFAULT 0,
    output_tokens INTEGER DEFAULT 0,
    cost_usd REAL DEFAULT 0,
    PRIMARY KEY (date, model, stage)
);

CREATE TABLE IF NOT EXISTS circuit_breakers (
    name TEXT PRIMARY KEY,
    state TEXT DEFAULT 'closed',
    -- closed, open, halfopen
    failures INTEGER DEFAULT 0,
    successes INTEGER DEFAULT 0,
    tripped_at TEXT,
    last_success_at TEXT,
    -- heartbeat: if now() - last_success_at > 2*interval, stage is stalled (Vida)
    last_update TEXT DEFAULT (datetime('now'))
);

CREATE TABLE IF NOT EXISTS audit_log (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    timestamp TEXT DEFAULT (datetime('now')),
    stage TEXT,
    event TEXT,
    detail TEXT
);

CREATE INDEX IF NOT EXISTS idx_sources_status ON sources(status);
CREATE INDEX IF NOT EXISTS idx_prs_status ON prs(status);
CREATE INDEX IF NOT EXISTS idx_prs_domain ON prs(domain);
CREATE INDEX IF NOT EXISTS idx_costs_date ON costs(date);
CREATE INDEX IF NOT EXISTS idx_audit_stage ON audit_log(stage);
"""


def get_connection(readonly: bool = False) -> sqlite3.Connection:
    """Create a SQLite connection with WAL mode and proper settings."""
    config.DB_PATH.parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(
        str(config.DB_PATH),
        timeout=30,
        isolation_level=None,  # autocommit — we manage transactions explicitly
    )
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA journal_mode=WAL")
    conn.execute("PRAGMA busy_timeout=10000")
    conn.execute("PRAGMA foreign_keys=ON")
    if readonly:
        conn.execute("PRAGMA query_only=ON")
    return conn


@contextmanager
def transaction(conn: sqlite3.Connection):
    """Context manager for explicit transactions."""
    conn.execute("BEGIN")
    try:
        yield conn
        conn.execute("COMMIT")
    except Exception:
        conn.execute("ROLLBACK")
        raise


def migrate(conn: sqlite3.Connection):
    """Run schema migrations."""
    conn.executescript(SCHEMA_SQL)

    # Check current version
    try:
        row = conn.execute("SELECT MAX(version) as v FROM schema_version").fetchone()
        current = row["v"] if row and row["v"] else 0
    except sqlite3.OperationalError:
        current = 0

    # --- Incremental migrations ---
    if current < 2:
        # Phase 2: add multiplayer columns to prs table
        for stmt in [
            "ALTER TABLE prs ADD COLUMN priority TEXT",
            "ALTER TABLE prs ADD COLUMN origin TEXT DEFAULT 'pipeline'",
            "ALTER TABLE prs ADD COLUMN last_error TEXT",
        ]:
            try:
                conn.execute(stmt)
            except sqlite3.OperationalError:
                pass  # Column already exists (idempotent)
        logger.info("Migration v2: added priority, origin, last_error to prs")

    if current < 3:
        # Phase 3: retry budget — track eval attempts and issue tags per PR
        for stmt in [
            "ALTER TABLE prs ADD COLUMN eval_attempts INTEGER DEFAULT 0",
            "ALTER TABLE prs ADD COLUMN eval_issues TEXT DEFAULT '[]'",
        ]:
            try:
                conn.execute(stmt)
            except sqlite3.OperationalError:
                pass  # Column already exists (idempotent)
        logger.info("Migration v3: added eval_attempts, eval_issues to prs")

    if current < SCHEMA_VERSION:
        conn.execute(
            "INSERT OR REPLACE INTO schema_version (version) VALUES (?)",
            (SCHEMA_VERSION,),
        )
        logger.info("Database migrated to schema version %d", SCHEMA_VERSION)
    else:
        logger.debug("Database at schema version %d", current)


def audit(conn: sqlite3.Connection, stage: str, event: str, detail: str = None):
    """Write an audit log entry."""
    conn.execute(
        "INSERT INTO audit_log (stage, event, detail) VALUES (?, ?, ?)",
        (stage, event, detail),
    )


def append_priority_log(conn: sqlite3.Connection, path: str, stage: str, priority: str, reasoning: str):
    """Append a priority assessment to a source's priority_log.

    NOTE: This does NOT update the source's priority column. The priority column
    is the authoritative priority, set only by initial triage or human override.
    The priority_log records each stage's opinion for offline calibration analysis.
    (Bug caught by Theseus — original version overwrote priority with each stage's opinion.)
    (Race condition fix per Vida — read-then-write wrapped in transaction.)
    """
    conn.execute("BEGIN")
    try:
        row = conn.execute("SELECT priority_log FROM sources WHERE path = ?", (path,)).fetchone()
        if not row:
            conn.execute("ROLLBACK")
            return
        log = json.loads(row["priority_log"] or "[]")
        log.append({"stage": stage, "priority": priority, "reasoning": reasoning})
        conn.execute(
            "UPDATE sources SET priority_log = ?, updated_at = datetime('now') WHERE path = ?",
            (json.dumps(log), path),
        )
        conn.execute("COMMIT")
    except Exception:
        conn.execute("ROLLBACK")
        raise


def set_priority(conn: sqlite3.Connection, path: str, priority: str, reason: str = "human override"):
    """Set a source's authoritative priority. Used for human overrides and initial triage."""
    conn.execute(
        "UPDATE sources SET priority = ?, updated_at = datetime('now') WHERE path = ?",
        (priority, path),
    )
    append_priority_log(conn, path, "override", priority, reason)