"""SQLite store for email migration jobs — Spec 019 / 013."""

from __future__ import annotations

import json
from datetime import datetime, timezone
from typing import Any


def _now() -> str:
    return datetime.now(timezone.utc).isoformat()


def init_schema(conn) -> None:
    conn.executescript(
        """
        CREATE TABLE IF NOT EXISTS migration_jobs (
            id INTEGER PRIMARY KEY,
            tenant_id INTEGER NOT NULL DEFAULT 1,
            ticket_id INTEGER,
            domain TEXT NOT NULL,
            phase TEXT NOT NULL DEFAULT 'discovered',
            migration_gate TEXT NOT NULL DEFAULT 'blocked',
            source_server_label TEXT,
            dest_imap_host TEXT,
            notes TEXT,
            approved_by TEXT,
            approved_at TEXT,
            dns_cutover_at TEXT,
            created_at TEXT NOT NULL,
            updated_at TEXT NOT NULL
        );
        CREATE TABLE IF NOT EXISTS migration_mailboxes (
            id INTEGER PRIMARY KEY,
            job_id INTEGER NOT NULL,
            email TEXT NOT NULL,
            source_type TEXT NOT NULL DEFAULT 'imap',
            source_host TEXT,
            source_user TEXT,
            credentials_ref TEXT,
            pst_path TEXT,
            folder_map_json TEXT,
            messages_source INTEGER NOT NULL DEFAULT 0,
            messages_dest INTEGER NOT NULL DEFAULT 0,
            bytes_source INTEGER NOT NULL DEFAULT 0,
            bytes_dest INTEGER NOT NULL DEFAULT 0,
            sync_percent REAL NOT NULL DEFAULT 0,
            last_error TEXT,
            status TEXT NOT NULL DEFAULT 'pending',
            created_at TEXT NOT NULL,
            updated_at TEXT NOT NULL,
            FOREIGN KEY (job_id) REFERENCES migration_jobs(id)
        );
        CREATE TABLE IF NOT EXISTS migration_runs (
            id INTEGER PRIMARY KEY,
            job_id INTEGER NOT NULL,
            mailbox_id INTEGER,
            run_type TEXT NOT NULL,
            tool TEXT NOT NULL,
            status TEXT NOT NULL DEFAULT 'queued',
            exit_code INTEGER,
            log_path TEXT,
            stats_json TEXT,
            started_at TEXT NOT NULL,
            finished_at TEXT,
            triggered_by TEXT,
            FOREIGN KEY (job_id) REFERENCES migration_jobs(id)
        );
        CREATE TABLE IF NOT EXISTS migration_gate_checks (
            id INTEGER PRIMARY KEY,
            job_id INTEGER NOT NULL,
            check_id TEXT NOT NULL,
            status TEXT NOT NULL,
            message TEXT,
            checked_at TEXT NOT NULL,
            FOREIGN KEY (job_id) REFERENCES migration_jobs(id)
        );
        CREATE TABLE IF NOT EXISTS migration_credentials (
            id TEXT PRIMARY KEY,
            mailbox_id INTEGER NOT NULL,
            secret_blob BLOB NOT NULL,
            created_at TEXT NOT NULL,
            expires_at TEXT
        );
        CREATE INDEX IF NOT EXISTS idx_migration_jobs_domain ON migration_jobs(domain);
        CREATE INDEX IF NOT EXISTS idx_migration_mailboxes_job ON migration_mailboxes(job_id);
        """
    )


def _job_dict(row) -> dict[str, Any]:
    return {
        "id": row["id"],
        "tenant_id": row["tenant_id"],
        "ticket_id": row["ticket_id"],
        "domain": row["domain"],
        "phase": row["phase"],
        "migration_gate": row["migration_gate"],
        "source_server_label": row["source_server_label"],
        "dest_imap_host": row["dest_imap_host"],
        "notes": row["notes"],
        "approved_by": row["approved_by"],
        "approved_at": row["approved_at"],
        "dns_cutover_at": row["dns_cutover_at"],
        "created_at": row["created_at"],
        "updated_at": row["updated_at"],
    }


def _mailbox_dict(row) -> dict[str, Any]:
    return {
        "id": row["id"],
        "job_id": row["job_id"],
        "email": row["email"],
        "source_type": row["source_type"],
        "source_host": row["source_host"],
        "source_user": row["source_user"],
        "credentials_ref": row["credentials_ref"],
        "pst_path": row["pst_path"],
        "folder_map_json": row["folder_map_json"],
        "messages_source": row["messages_source"],
        "messages_dest": row["messages_dest"],
        "bytes_source": row["bytes_source"],
        "bytes_dest": row["bytes_dest"],
        "sync_percent": row["sync_percent"],
        "last_error": row["last_error"],
        "status": row["status"],
        "created_at": row["created_at"],
        "updated_at": row["updated_at"],
    }


def _run_dict(row) -> dict[str, Any]:
    stats = {}
    if row["stats_json"]:
        try:
            stats = json.loads(row["stats_json"])
        except json.JSONDecodeError:
            stats = {}
    return {
        "id": row["id"],
        "job_id": row["job_id"],
        "mailbox_id": row["mailbox_id"],
        "run_type": row["run_type"],
        "tool": row["tool"],
        "status": row["status"],
        "exit_code": row["exit_code"],
        "log_path": row["log_path"],
        "stats": stats,
        "started_at": row["started_at"],
        "finished_at": row["finished_at"],
        "triggered_by": row["triggered_by"],
    }


def list_jobs(conn, *, domain: str | None = None, limit: int = 100) -> dict[str, Any]:
    limit = max(1, min(limit, 500))
    if domain:
        rows = conn.execute(
            "SELECT * FROM migration_jobs WHERE domain = ? ORDER BY id DESC LIMIT ?",
            (domain.strip().lower(), limit),
        ).fetchall()
        total = conn.execute(
            "SELECT COUNT(*) FROM migration_jobs WHERE domain = ?",
            (domain.strip().lower(),),
        ).fetchone()[0]
    else:
        rows = conn.execute(
            "SELECT * FROM migration_jobs ORDER BY id DESC LIMIT ?",
            (limit,),
        ).fetchall()
        total = conn.execute("SELECT COUNT(*) FROM migration_jobs").fetchone()[0]
    return {"jobs": [_job_dict(r) for r in rows], "total": total}


def get_job(conn, job_id: int) -> dict[str, Any] | None:
    row = conn.execute("SELECT * FROM migration_jobs WHERE id = ?", (job_id,)).fetchone()
    if not row:
        return None
    job = _job_dict(row)
    mboxes = conn.execute(
        "SELECT * FROM migration_mailboxes WHERE job_id = ? ORDER BY id",
        (job_id,),
    ).fetchall()
    runs = conn.execute(
        "SELECT * FROM migration_runs WHERE job_id = ? ORDER BY id DESC LIMIT 20",
        (job_id,),
    ).fetchall()
    checks = conn.execute(
        "SELECT * FROM migration_gate_checks WHERE job_id = ? ORDER BY id DESC LIMIT 20",
        (job_id,),
    ).fetchall()
    job["mailboxes"] = [_mailbox_dict(m) for m in mboxes]
    job["runs"] = [_run_dict(r) for r in runs]
    job["gate_checks"] = [
        {
            "id": c["id"],
            "check_id": c["check_id"],
            "status": c["status"],
            "message": c["message"],
            "checked_at": c["checked_at"],
        }
        for c in checks
    ]
    if job["mailboxes"]:
        avg = sum(m["sync_percent"] for m in job["mailboxes"]) / len(job["mailboxes"])
        job["sync_percent_avg"] = round(avg, 2)
    else:
        job["sync_percent_avg"] = 0.0
    return job


def create_job(
    conn,
    *,
    domain: str,
    tenant_id: int = 1,
    ticket_id: int | None = None,
    source_server_label: str = "",
    dest_imap_host: str = "",
    notes: str = "",
    mailboxes: list[dict] | None = None,
) -> dict[str, Any]:
    now = _now()
    dom = domain.strip().lower()
    cur = conn.execute(
        """
        INSERT INTO migration_jobs
        (tenant_id, ticket_id, domain, phase, migration_gate, source_server_label,
         dest_imap_host, notes, created_at, updated_at)
        VALUES (?, ?, ?, 'discovered', 'blocked', ?, ?, ?, ?, ?)
        """,
        (tenant_id, ticket_id, dom, source_server_label[:200], dest_imap_host[:200], notes[:2000], now, now),
    )
    job_id = int(cur.lastrowid)
    for mb in mailboxes or []:
        email = (mb.get("email") or "").strip().lower()
        if not email:
            continue
        conn.execute(
            """
            INSERT INTO migration_mailboxes
            (job_id, email, source_type, source_host, source_user, status, created_at, updated_at)
            VALUES (?, ?, ?, ?, ?, 'pending', ?, ?)
            """,
            (
                job_id,
                email,
                mb.get("source_type") or "imap",
                (mb.get("source_host") or "")[:200] or None,
                (mb.get("source_user") or email)[:200] or None,
                now,
                now,
            ),
        )
    conn.commit()
    return get_job(conn, job_id) or {}


def update_job(conn, job_id: int, **fields) -> dict[str, Any] | None:
    allowed = {
        "phase",
        "migration_gate",
        "source_server_label",
        "dest_imap_host",
        "notes",
        "approved_by",
        "approved_at",
        "dns_cutover_at",
        "ticket_id",
    }
    sets = []
    params: list[Any] = []
    for key, val in fields.items():
        if key in allowed:
            sets.append(f"{key} = ?")
            params.append(val)
    if not sets:
        return get_job(conn, job_id)
    sets.append("updated_at = ?")
    params.append(_now())
    params.append(job_id)
    conn.execute(f"UPDATE migration_jobs SET {', '.join(sets)} WHERE id = ?", params)
    conn.commit()
    return get_job(conn, job_id)


def add_run(
    conn,
    *,
    job_id: int,
    run_type: str,
    tool: str,
    triggered_by: str,
    mailbox_id: int | None = None,
    status: str = "running",
    stats: dict | None = None,
    exit_code: int | None = None,
    log_path: str | None = None,
) -> dict[str, Any]:
    now = _now()
    cur = conn.execute(
        """
        INSERT INTO migration_runs
        (job_id, mailbox_id, run_type, tool, status, exit_code, log_path, stats_json,
         started_at, finished_at, triggered_by)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
        """,
        (
            job_id,
            mailbox_id,
            run_type,
            tool,
            status,
            exit_code,
            log_path,
            json.dumps(stats or {}),
            now,
            now if status != "running" else None,
            triggered_by,
        ),
    )
    conn.commit()
    row = conn.execute("SELECT * FROM migration_runs WHERE id = ?", (int(cur.lastrowid),)).fetchone()
    return _run_dict(row)


def finish_run(conn, run_id: int, *, status: str, exit_code: int | None = None, stats: dict | None = None) -> None:
    conn.execute(
        """
        UPDATE migration_runs
        SET status = ?, exit_code = ?, stats_json = COALESCE(?, stats_json),
            finished_at = ?
        WHERE id = ?
        """,
        (status, exit_code, json.dumps(stats) if stats else None, _now(), run_id),
    )
    conn.commit()


def update_mailbox_sync(
    conn,
    mailbox_id: int,
    *,
    messages_source: int,
    messages_dest: int,
    sync_percent: float,
    status: str = "ok",
    last_error: str | None = None,
) -> None:
    conn.execute(
        """
        UPDATE migration_mailboxes
        SET messages_source = ?, messages_dest = ?, sync_percent = ?,
            status = ?, last_error = ?, updated_at = ?
        WHERE id = ?
        """,
        (messages_source, messages_dest, sync_percent, status, last_error, _now(), mailbox_id),
    )
    conn.commit()


def add_gate_check(conn, job_id: int, check_id: str, status: str, message: str) -> None:
    conn.execute(
        """
        INSERT INTO migration_gate_checks (job_id, check_id, status, message, checked_at)
        VALUES (?, ?, ?, ?, ?)
        """,
        (job_id, check_id, status, message[:500], _now()),
    )
    conn.commit()


def get_gate_for_domain(conn, domain: str) -> dict[str, Any]:
    dom = domain.strip().lower()
    row = conn.execute(
        """
        SELECT * FROM migration_jobs
        WHERE domain = ? AND phase NOT IN ('closed', 'failed')
        ORDER BY id DESC LIMIT 1
        """,
        (dom,),
    ).fetchone()
    if not row:
        return {
            "domain": dom,
            "gate": "ready_for_dns",
            "reason": "no_active_migration_job",
            "job_id": None,
        }
    job = _job_dict(row)
    return {
        "domain": dom,
        "gate": job["migration_gate"],
        "phase": job["phase"],
        "job_id": job["id"],
        "approved_by": job["approved_by"],
        "sync_percent_avg": get_job(conn, job["id"]).get("sync_percent_avg", 0) if job["id"] else 0,
    }