"""JSON API (§8). No auth in v1 — LAN-only, single admin view (§12)."""

from __future__ import annotations

import csv
import io
import json
import logging
import time

from flask import Blueprint, Response, current_app, jsonify, request

from . import keeps, queries, scanner
from .rules import RuleError
from .keeps import KeepError

log = logging.getLogger(__name__)

bp = Blueprint("api", __name__, url_prefix="/api/v1")


def db():
    return current_app.extensions["mediashelf"]["db"]


def cfg():
    return current_app.extensions["mediashelf"]["config"]


@bp.errorhandler(RuleError)
def _rule_error(e):
    return jsonify({"error": "invalid_rule", "message": str(e)}), 400


@bp.errorhandler(KeepError)
def _keep_error(e):
    return jsonify({"error": "invalid_keep", "message": str(e)}), 400


def _json_arg(name):
    raw = request.args.get(name)
    if not raw:
        return None
    try:
        return json.loads(raw)
    except (TypeError, ValueError):
        raise RuleError("%s must be valid JSON" % name)


def _bool_arg(name, default=False):
    v = request.args.get(name)
    if v is None:
        return default
    return v.lower() in ("1", "true", "yes")


def _query_kwargs():
    rule_group = _json_arg("rules")
    weights = _json_arg("weights")

    view_id = request.args.get("view_id")
    sort = request.args.get("sort")
    if view_id:
        row = db().one("SELECT * FROM saved_view WHERE id = ?", (view_id,))
        if row is None:
            raise RuleError("no such view")
        rule_group = json.loads(row["rules"]) if row["rules"] else None
        sort = sort or row["sort"]
        if row["weights"] and not weights:
            weights = json.loads(row["weights"])

    return dict(
        library_ids=request.args.getlist("library_id") or None,
        kinds=request.args.getlist("kind") or None,
        q=request.args.get("q"),
        rule_group=rule_group,
        include_missing=_bool_arg("include_missing"),
        include_kept=_bool_arg("include_kept"),
        include_shows=_bool_arg("include_shows"),
        weights=weights,
    ), sort


# ── items ────────────────────────────────────────────────────────────────

@bp.get("/items")
def items():
    kw, sort = _query_kwargs()
    q = queries.Query(db(), cfg())
    return jsonify(q.page(
        sort=sort,
        page=int(request.args.get("page", 1)),
        page_size=int(request.args.get("page_size", 100)),
        **kw,
    ))


@bp.get("/items/<int:item_id>")
def item_detail(item_id):
    d = db()
    q = queries.Query(d, cfg())
    expr, where, params = q.build(include_kept=True, include_missing=True, include_shows=True)
    params["item_id"] = item_id
    sql = ("SELECT " + queries.BASE_COLUMNS + ", " + expr + " AS reclaim_score, "
           + "NULL AS grace, COALESCE(d.dupe_count,1) AS duplicate_count "
           + queries.FROM_CLAUSE + " WHERE i.id = :item_id")
    row = d.one(sql, params)
    if row is None:
        return jsonify({"error": "not_found"}), 404

    out = q.serialize(row)
    out["parts"] = [dict(r) for r in d.query(
        "SELECT * FROM media_part WHERE media_item_id = ? ORDER BY file_path", (item_id,))]

    if out["kind"] == "season":
        out["episodes"] = [dict(r) for r in d.query(
            "SELECT * FROM episode WHERE season_item_id = ? ORDER BY episode_number",
            (item_id,))]
        pids = [e["provider_item_id"] for e in out["episodes"]]
    else:
        pids = [d.scalar("SELECT provider_item_id FROM media_item WHERE id=?", (item_id,))]

    if pids:
        marks = ",".join("?" * len(pids))
        out["watch_history"] = [dict(r) for r in d.query(
            "SELECT w.viewed_at, w.percent_complete, w.disposition, w.account_id, "
            "COALESCE(a.friendly_name, a.name, w.account_id) AS who, w.platform "
            "FROM watch_event w LEFT JOIN account a ON a.account_id = w.account_id "
            f"WHERE w.provider_item_id IN ({marks}) ORDER BY w.viewed_at DESC LIMIT 500",
            tuple(pids))]
    else:
        out["watch_history"] = []

    if out.get("guid"):
        out["duplicates"] = [dict(r) for r in d.query(
            "SELECT i.id, i.title, i.size_bytes, i.resolution, i.watch_count, "
            "lib.title AS library_title FROM media_item i "
            "JOIN library lib ON lib.id=i.library_id "
            "WHERE i.guid = ? AND i.id != ? AND i.kind='movie' AND i.status='present'",
            (out["guid"], item_id))]
    return jsonify(out)


@bp.get("/libraries")
def libraries():
    return jsonify({"libraries": queries.size_by_library(db())})


@bp.get("/accounts")
def accounts():
    return jsonify({"accounts": [dict(r) for r in db().query(
        "SELECT a.*, (SELECT COUNT(*) FROM watch_event w WHERE w.account_id=a.account_id) "
        "AS plays FROM account a ORDER BY plays DESC")]})


# ── stats ────────────────────────────────────────────────────────────────

@bp.get("/stats/overview")
def stats_overview():
    return jsonify(queries.overview(db(), cfg()))


@bp.get("/stats/size-by-library")
def stats_size_by_library():
    return jsonify({"libraries": queries.size_by_library(db())})


@bp.get("/stats/added-over-time")
def stats_added_over_time():
    return jsonify({"buckets": queries.added_over_time(
        db(), request.args.get("bucket", "month"))})


@bp.get("/stats/completion")
def stats_completion():
    return jsonify(queries.completion_split(db()))


@bp.get("/stats/size-vs-lastwatched")
def stats_scatter():
    return jsonify({"points": queries.size_vs_lastwatched(db())})


@bp.get("/stats/watch-distribution")
def stats_watch_distribution():
    return jsonify({"buckets": [dict(r) for r in db().query("""
        SELECT CASE WHEN watch_count = 0 THEN '0'
                    WHEN watch_count = 1 THEN '1'
                    WHEN watch_count <= 3 THEN '2-3'
                    WHEN watch_count <= 10 THEN '4-10'
                    ELSE '10+' END AS bucket,
               COUNT(*) AS items, COALESCE(SUM(size_bytes),0) AS size_bytes
        FROM media_item WHERE kind IN ('movie','season') AND status='present'
        GROUP BY bucket""")]})


@bp.get("/duplicates")
def duplicates():
    groups = queries.duplicate_groups(db())
    return jsonify({
        "groups": groups,
        "total_redundant_bytes": sum(g["redundant_bytes"] for g in groups),
        "group_count": len(groups),
    })


@bp.get("/sources")
def sources():
    d = db()
    c = cfg()
    cov = [dict(r) for r in d.query("SELECT * FROM history_coverage")]
    return jsonify({
        "plex": {"configured": c.plex_configured, "base_url": c.plex_base_url},
        "tautulli": {"configured": c.tautulli_configured, "base_url": c.tautulli_base_url},
        "history_source": (cov[0]["source"] if cov else None),
        "has_completion_data": queries.history_has_completion(d),
        "coverage": cov,
        "providers": [dict(r) for r in d.query("SELECT * FROM provider")],
    })


# ── keep marks (§8.2) ────────────────────────────────────────────────────

@bp.get("/keeps")
def list_keeps():
    d = db()
    counts = keeps.mark_matches(d)
    rows = []
    for r in d.query(
        "SELECT k.*, lib.title AS library_title FROM keep_mark k "
        "JOIN library lib ON lib.id = k.library_id ORDER BY k.created_at DESC"
    ):
        item = dict(r)
        item["resolved_items"] = counts.get(r["id"], 0)
        item["resolved_bytes"] = d.scalar(
            "SELECT COALESCE(SUM(size_bytes),0) FROM media_item WHERE kept_mark_id = ?",
            (r["id"],)) or 0
        item["orphaned"] = item["resolved_items"] == 0
        rows.append(item)
    libs = [dict(r) for r in d.query(
        "SELECT id, title, keep_all FROM library WHERE keep_all = 1 ORDER BY title")]
    return jsonify({
        "marks": rows,
        "library_rules": libs,
        "orphan_count": sum(1 for r in rows if r["orphaned"]),
        "kept_bytes": d.scalar("SELECT COALESCE(SUM(size_bytes),0) FROM media_item "
                               "WHERE kept=1 AND kind IN ('movie','season')") or 0,
        "kept_items": d.scalar("SELECT COUNT(*) FROM media_item "
                               "WHERE kept=1 AND kind IN ('movie','season')") or 0,
    })


@bp.get("/keeps/orphans")
def keep_orphans():
    d = db()
    counts = keeps.mark_matches(d)
    ids = [k for k, v in counts.items() if v == 0]
    if not ids:
        return jsonify({"marks": []})
    marks = ",".join("?" * len(ids))
    return jsonify({"marks": [dict(r) for r in d.query(
        f"SELECT k.*, lib.title AS library_title FROM keep_mark k "
        f"JOIN library lib ON lib.id=k.library_id WHERE k.id IN ({marks})", tuple(ids))]})


@bp.post("/keeps")
def create_keep():
    payload = request.get_json(silent=True) or {}
    d = db()
    mode = payload.get("mode", "keep")
    note = payload.get("note")
    if payload.get("item_id"):
        mark_id = keeps.create_from_item(d, int(payload["item_id"]), mode, note)
    else:
        required = ("scope", "library_id", "guid")
        if not all(payload.get(k) for k in required):
            raise KeepError("need item_id, or scope + library_id + guid")
        mark_id = keeps.upsert(
            d, payload["scope"], mode, int(payload["library_id"]), payload["guid"],
            payload.get("season_number"), label=payload.get("label") or payload["guid"],
            note=note)
    keeps.resolve_all(d)
    row = d.one("SELECT * FROM keep_mark WHERE id = ?", (mark_id,))
    counts = keeps.mark_matches(d)
    out = dict(row)
    out["resolved_items"] = counts.get(mark_id, 0)
    out["resolved_bytes"] = d.scalar(
        "SELECT COALESCE(SUM(size_bytes),0) FROM media_item WHERE kept_mark_id=?",
        (mark_id,)) or 0
    return jsonify(out), 201


@bp.post("/keeps/bulk")
def bulk_keep():
    payload = request.get_json(silent=True) or {}
    ids = payload.get("item_ids") or []
    if not isinstance(ids, list) or not ids:
        raise KeepError("item_ids must be a non-empty list")
    if len(ids) > 5000:
        raise KeepError("too many items in one request")
    mode = payload.get("mode", "keep")
    note = payload.get("note")
    d = db()
    created, failed = [], []
    for item_id in ids:
        try:
            created.append(keeps.create_from_item(d, int(item_id), mode, note))
        except KeepError as e:
            failed.append({"item_id": item_id, "reason": str(e)})
    keeps.resolve_all(d)
    return jsonify({
        "created": len(created), "failed": failed,
        "kept_bytes": d.scalar("SELECT COALESCE(SUM(size_bytes),0) FROM media_item "
                               "WHERE kept=1 AND kind IN ('movie','season')") or 0,
    })


@bp.patch("/keeps/<int:mark_id>")
def patch_keep(mark_id):
    payload = request.get_json(silent=True) or {}
    db().execute("UPDATE keep_mark SET note=?, updated_at=? WHERE id=?",
                 (payload.get("note"), int(time.time()), mark_id))
    return jsonify({"ok": True})


@bp.delete("/keeps/<int:mark_id>")
def delete_keep(mark_id):
    d = db()
    ok = keeps.delete(d, mark_id)
    keeps.resolve_all(d)
    return jsonify({"deleted": ok}), (200 if ok else 404)


@bp.put("/libraries/<int:library_id>/keep_all")
def library_keep_all(library_id):
    payload = request.get_json(silent=True) or {}
    d = db()
    keeps.set_library_keep_all(d, library_id, bool(payload.get("keep_all")))
    keeps.resolve_all(d)
    return jsonify({"ok": True, "library_id": library_id,
                    "keep_all": bool(payload.get("keep_all"))})


@bp.get("/keeps/export")
def export_keeps():
    return Response(json.dumps(keeps.export(db()), indent=2),
                    mimetype="application/json",
                    headers={"Content-Disposition": "attachment; filename=keeps.json"})


@bp.post("/keeps/import")
def import_keeps():
    payload = request.get_json(silent=True) or {}
    return jsonify(keeps.import_(db(), payload))


# ── saved views (§8.3) ───────────────────────────────────────────────────

@bp.get("/views")
def list_views():
    return jsonify({"views": [dict(r) for r in db().query(
        "SELECT * FROM saved_view ORDER BY builtin DESC, name")]})


@bp.post("/views")
def create_view():
    p = request.get_json(silent=True) or {}
    if not p.get("name"):
        return jsonify({"error": "name is required"}), 400
    now = int(time.time())
    cur = db().execute(
        "INSERT INTO saved_view (name, description, rules, sort, columns, weights, "
        "created_at, updated_at) VALUES (?,?,?,?,?,?,?,?)",
        (p["name"], p.get("description"), json.dumps(p.get("rules") or {}),
         p.get("sort"), json.dumps(p.get("columns") or []),
         json.dumps(p.get("weights") or {}), now, now))
    return jsonify(dict(db().one("SELECT * FROM saved_view WHERE id=?", (cur.lastrowid,)))), 201


@bp.get("/views/<int:view_id>")
def get_view(view_id):
    row = db().one("SELECT * FROM saved_view WHERE id=?", (view_id,))
    return (jsonify(dict(row)), 200) if row else (jsonify({"error": "not_found"}), 404)


@bp.put("/views/<int:view_id>")
def update_view(view_id):
    p = request.get_json(silent=True) or {}
    db().execute(
        "UPDATE saved_view SET name=COALESCE(?,name), description=?, rules=?, sort=?, "
        "columns=?, weights=?, updated_at=? WHERE id=?",
        (p.get("name"), p.get("description"), json.dumps(p.get("rules") or {}),
         p.get("sort"), json.dumps(p.get("columns") or []),
         json.dumps(p.get("weights") or {}), int(time.time()), view_id))
    return jsonify({"ok": True})


@bp.delete("/views/<int:view_id>")
def delete_view(view_id):
    cur = db().execute("DELETE FROM saved_view WHERE id=? AND builtin=0", (view_id,))
    return jsonify({"deleted": cur.rowcount > 0})


# ── scans (§8.4) ─────────────────────────────────────────────────────────

@bp.get("/scans")
def list_scans():
    return jsonify({"scans": [dict(r) for r in db().query(
        "SELECT * FROM scan ORDER BY id DESC LIMIT 50")]})


@bp.get("/scans/current")
def current_scan():
    row = db().one("SELECT * FROM scan WHERE status='running' ORDER BY id DESC LIMIT 1")
    return jsonify(dict(row) if row else None)


@bp.post("/scans")
def start_scan():
    p = request.get_json(silent=True) or {}
    mode = p.get("mode", "incremental")
    if mode not in ("full", "incremental"):
        return jsonify({"error": "mode must be 'full' or 'incremental'"}), 400
    started = scanner.start_background_scan(current_app, mode, "manual")
    if not started:
        return jsonify({"error": "a scan is already running"}), 409
    return jsonify({"status": "started", "mode": mode}), 202


# ── export (§8.5) ────────────────────────────────────────────────────────

CSV_COLUMNS = [
    "id", "kind", "library", "title", "show_title", "season_number", "year",
    "size_bytes", "size_human", "added_at_iso", "last_watched_at_iso",
    "watch_count", "partial_count", "abandoned_count", "distinct_watcher_count",
    "episode_count", "part_count", "resolution", "duplicate_count",
    "pre_history", "kept", "kept_via", "reclaim_score", "primary_path",
]


def _human(n):
    n = float(n or 0)
    for u in ("B", "KB", "MB", "GB", "TB", "PB"):
        if abs(n) < 1024:
            return "%.1f %s" % (n, u)
        n /= 1024.0
    return "%.1f EB" % n


def _iso(ts):
    if not ts:
        return ""
    return time.strftime("%Y-%m-%d", time.localtime(int(ts)))


@bp.get("/export.csv")
def export_csv():
    kw, sort = _query_kwargs()
    d = db()
    q = queries.Query(d, cfg())

    def generate():
        buf = io.StringIO()
        w = csv.writer(buf)
        w.writerow(CSV_COLUMNS)
        yield buf.getvalue()
        buf.seek(0), buf.truncate(0)
        for row in q.iter_all(sort=sort, **kw):
            r = dict(row)
            w.writerow([
                r["id"], r["kind"], r["library_title"], r["title"],
                r.get("show_title") or "", r.get("season_number") or "",
                r.get("year") or "", r.get("size_bytes") or 0,
                _human(r.get("size_bytes")), _iso(r.get("added_at")),
                _iso(r.get("last_watched_at")), r.get("watch_count") or 0,
                r.get("partial_count") or 0, r.get("abandoned_count") or 0,
                r.get("distinct_watcher_count") or 0,
                r.get("episode_count") if r["kind"] == "season" else "",
                r.get("part_count") or 0, r.get("resolution") or "",
                r.get("duplicate_count") or 1,
                "yes" if r.get("pre_history") else "no",
                "yes" if r.get("kept") else "no", r.get("kept_via") or "",
                r.get("reclaim_score"), r.get("primary_path") or "",
            ])
            yield buf.getvalue()
            buf.seek(0), buf.truncate(0)

    stamp = time.strftime("%Y%m%d-%H%M")
    return Response(generate(), mimetype="text/csv", headers={
        "Content-Disposition": "attachment; filename=mediashelf-%s.csv" % stamp})


# ── settings ─────────────────────────────────────────────────────────────

@bp.get("/settings")
def settings():
    return jsonify(cfg().redacted())