import { readFile, rename, writeFile } from "node:fs/promises";
import { join } from "node:path";
import { createClient, type SupabaseClient } from "@supabase/supabase-js";
import type { AppState, Asset, GenerationCapability, GenerationJob, GenerationStatus, Project, UsageEvent } from "@/lib/types";
import { createId } from "@/lib/server/ids";
import { dataDir, DEFAULT_OWNER_ID, ensureRuntimeDirs } from "@/lib/server/runtime";

const STORE_FILE = "web-app-state.json";
let localWriteQueue: Promise<unknown> = Promise.resolve();

type AssetInput = Omit<Asset, "id" | "createdAt" | "updatedAt"> & Partial<Pick<Asset, "id" | "createdAt" | "updatedAt">>;
type JobInput = Omit<GenerationJob, "id" | "createdAt" | "updatedAt"> & Partial<Pick<GenerationJob, "id" | "createdAt" | "updatedAt">>;
type UsageInput = Omit<UsageEvent, "id" | "createdAt"> & Partial<Pick<UsageEvent, "id" | "createdAt">>;

export type GenerationJobListFilters = {
  ownerId?: string;
  externalClientId?: string;
  status?: GenerationStatus;
  capability?: GenerationCapability;
  limit?: number;
  before?: string;
};

export type ClaimGenerationJobsInput = {
  workerId: string;
  limit?: number;
  lockTimeoutMs?: number;
};

export async function listAssets(ownerId = DEFAULT_OWNER_ID): Promise<Asset[]> {
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase
      .from("assets")
      .select("*")
      .eq("owner_id", ownerId)
      .order("created_at", { ascending: false });
    if (error) throw new Error(error.message);
    return (data || []).map(assetFromRow);
  }
  const state = await readState();
  return state.assets.filter((asset) => asset.ownerId === ownerId).sort(sortNewest);
}

export async function getAsset(id: string): Promise<Asset | null> {
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.from("assets").select("*").eq("id", id).maybeSingle();
    if (error) throw new Error(error.message);
    return data ? assetFromRow(data) : null;
  }
  const state = await readState();
  return state.assets.find((asset) => asset.id === id) || null;
}

export async function getAssetByStoragePath(storagePath: string): Promise<Asset | null> {
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.from("assets").select("*").eq("storage_path", storagePath).maybeSingle();
    if (error) throw new Error(error.message);
    return data ? assetFromRow(data) : null;
  }
  const state = await readState();
  return state.assets.find((asset) => asset.storagePath === storagePath) || null;
}

export async function createAsset(input: AssetInput): Promise<Asset> {
  const now = new Date().toISOString();
  const asset: Asset = {
    ...input,
    id: input.id || createId("asset"),
    ownerId: input.ownerId || DEFAULT_OWNER_ID,
    tags: input.tags || [],
    metadata: input.metadata || {},
    createdAt: input.createdAt || now,
    updatedAt: input.updatedAt || now
  };
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.from("assets").insert(assetToRow(asset)).select("*").single();
    if (error) throw new Error(error.message);
    return assetFromRow(data);
  }
  return mutateLocalState((state) => {
    state.assets.unshift(asset);
    return asset;
  });
}

export async function deleteAsset(id: string): Promise<Asset | null> {
  const existing = await getAsset(id);
  if (!existing) return null;
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { error } = await supabase.from("assets").delete().eq("id", id);
    if (error) throw new Error(error.message);
    return existing;
  }
  return mutateLocalState((state) => {
    state.assets = state.assets.filter((asset) => asset.id !== id);
    state.generationJobs = state.generationJobs.map((job) => ({
      ...job,
      inputAssetIds: job.inputAssetIds.filter((assetId) => assetId !== id),
      outputAssetIds: job.outputAssetIds.filter((assetId) => assetId !== id)
    }));
    return existing;
  });
}

export async function listGenerationJobs(ownerId = DEFAULT_OWNER_ID, limit = 200): Promise<GenerationJob[]> {
  return listGenerationJobsFiltered({ ownerId, limit });
}

export async function listGenerationJobsFiltered(filters: GenerationJobListFilters = {}): Promise<GenerationJob[]> {
  const ownerId = filters.ownerId || DEFAULT_OWNER_ID;
  const limit = filters.limit || 200;
  const supabase = getSupabaseAdmin();
  if (supabase) {
    let query = supabase
      .from("generation_jobs")
      .select("*")
      .eq("owner_id", ownerId)
      .order("created_at", { ascending: false })
      .limit(limit);
    if (filters.externalClientId) query = query.eq("external_client_id", filters.externalClientId);
    if (filters.status) query = query.eq("status", filters.status);
    if (filters.capability) query = query.eq("capability", filters.capability);
    if (filters.before) query = query.lt("created_at", filters.before);
    const { data, error } = await query;
    if (error) throw new Error(error.message);
    return (data || []).map(jobFromRow);
  }
  const state = await readState();
  return state.generationJobs
    .filter((job) => job.ownerId === ownerId)
    .filter((job) => !filters.externalClientId || job.externalClientId === filters.externalClientId)
    .filter((job) => !filters.status || job.status === filters.status)
    .filter((job) => !filters.capability || job.capability === filters.capability)
    .filter((job) => !filters.before || job.createdAt < filters.before)
    .sort(sortNewest)
    .slice(0, limit);
}

export async function getGenerationJob(id: string): Promise<GenerationJob | null> {
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.from("generation_jobs").select("*").eq("id", id).maybeSingle();
    if (error) throw new Error(error.message);
    return data ? jobFromRow(data) : null;
  }
  const state = await readState();
  return state.generationJobs.find((job) => job.id === id) || null;
}

export async function createGenerationJob(input: JobInput): Promise<GenerationJob> {
  const now = new Date().toISOString();
  const job: GenerationJob = {
    ...input,
    id: input.id || createId("job"),
    ownerId: input.ownerId || DEFAULT_OWNER_ID,
    inputAssetIds: input.inputAssetIds || [],
    inputUrls: input.inputUrls || [],
    outputAssetIds: input.outputAssetIds || [],
    requestPayload: input.requestPayload || {},
    priority: input.priority ?? 0,
    attempts: input.attempts ?? 0,
    maxAttempts: input.maxAttempts ?? 3,
    scheduledAt: input.scheduledAt || now,
    webhookAttempts: input.webhookAttempts ?? 0,
    createdAt: input.createdAt || now,
    updatedAt: input.updatedAt || now
  };
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.from("generation_jobs").insert(jobToRow(job)).select("*").single();
    if (error) throw new Error(error.message);
    return jobFromRow(data);
  }
  return mutateLocalState((state) => {
    state.generationJobs.unshift(job);
    return job;
  });
}

export async function findGenerationJobByIdempotency(
  externalClientId: string,
  idempotencyKey: string,
  ownerId = DEFAULT_OWNER_ID
): Promise<GenerationJob | null> {
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase
      .from("generation_jobs")
      .select("*")
      .eq("owner_id", ownerId)
      .eq("external_client_id", externalClientId)
      .eq("idempotency_key", idempotencyKey)
      .maybeSingle();
    if (error) throw new Error(error.message);
    return data ? jobFromRow(data) : null;
  }
  const state = await readState();
  return state.generationJobs.find((job) => (
    job.ownerId === ownerId &&
    job.externalClientId === externalClientId &&
    job.idempotencyKey === idempotencyKey
  )) || null;
}

export async function claimGenerationJobs(input: ClaimGenerationJobsInput): Promise<GenerationJob[]> {
  const limit = Math.max(1, Math.min(input.limit || 1, 20));
  const lockTimeoutMs = input.lockTimeoutMs ?? 5 * 60 * 1000;
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.rpc("claim_generation_jobs", {
      p_worker_id: input.workerId,
      p_limit: limit,
      p_lock_timeout_seconds: Math.ceil(lockTimeoutMs / 1000)
    });
    if (error) throw new Error(`claim_generation_jobs failed: ${error.message}`);
    return (Array.isArray(data) ? data : []).map(jobFromRow);
  }

  return mutateLocalState((state) => {
    const now = new Date();
    const nowIso = now.toISOString();
    const staleBefore = new Date(now.getTime() - lockTimeoutMs).toISOString();
    const selected = state.generationJobs
      .filter((job) => isClaimableJob(job, nowIso, staleBefore))
      .sort(sortClaimableJobs)
      .slice(0, limit);
    for (const job of selected) {
      job.lockedAt = nowIso;
      job.lockedBy = input.workerId;
      if (!job.startedAt) job.startedAt = nowIso;
      job.updatedAt = nowIso;
    }
    return selected.map((job) => ({ ...job }));
  });
}

export async function clearGenerationJobLock(
  id: string,
  patch: Partial<GenerationJob> = {},
  options: { clearProviderTaskId?: boolean } = {}
): Promise<GenerationJob> {
  const updatedAt = new Date().toISOString();
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase
      .from("generation_jobs")
      .update({
        ...jobToRow({ ...patch, updatedAt } as GenerationJob),
        locked_at: null,
        locked_by: null,
        ...(options.clearProviderTaskId ? { provider_task_id: null } : {})
      })
      .eq("id", id)
      .select("*")
      .single();
    if (error) throw new Error(error.message);
    return jobFromRow(data);
  }
  return mutateLocalState((state) => {
    const index = state.generationJobs.findIndex((job) => job.id === id);
    if (index === -1) throw new Error(`Generation job not found: ${id}`);
    state.generationJobs[index] = {
      ...state.generationJobs[index],
      ...patch,
      lockedAt: undefined,
      lockedBy: undefined,
      ...(options.clearProviderTaskId ? { providerTaskId: undefined } : {}),
      updatedAt
    };
    return state.generationJobs[index];
  });
}

export async function updateGenerationJob(id: string, patch: Partial<GenerationJob>): Promise<GenerationJob> {
  const updatedAt = new Date().toISOString();
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase
      .from("generation_jobs")
      .update(jobToRow({ ...patch, updatedAt } as GenerationJob))
      .eq("id", id)
      .select("*")
      .single();
    if (error) throw new Error(error.message);
    return jobFromRow(data);
  }
  return mutateLocalState((state) => {
    const index = state.generationJobs.findIndex((job) => job.id === id);
    if (index === -1) throw new Error(`Generation job not found: ${id}`);
    state.generationJobs[index] = { ...state.generationJobs[index], ...patch, updatedAt };
    return state.generationJobs[index];
  });
}

export async function deleteGenerationJob(id: string): Promise<GenerationJob | null> {
  const existing = await getGenerationJob(id);
  if (!existing) return null;
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { error: usageError } = await supabase.from("usage_events").delete().eq("job_id", id);
    if (usageError) throw new Error(usageError.message);
    const { error } = await supabase.from("generation_jobs").delete().eq("id", id);
    if (error) throw new Error(error.message);
    return existing;
  }
  return mutateLocalState((state) => {
    state.generationJobs = state.generationJobs.filter((job) => job.id !== id);
    state.usageEvents = state.usageEvents.filter((event) => event.jobId !== id);
    return existing;
  });
}

export async function recordUsageEvent(input: UsageInput): Promise<UsageEvent> {
  const usage: UsageEvent = {
    ...input,
    id: input.id || createId("usage"),
    ownerId: input.ownerId || DEFAULT_OWNER_ID,
    createdAt: input.createdAt || new Date().toISOString()
  };
  const supabase = getSupabaseAdmin();
  if (supabase) {
    const { data, error } = await supabase.from("usage_events").insert(usageToRow(usage)).select("*").single();
    if (error) throw new Error(error.message);
    return usageFromRow(data);
  }
  return mutateLocalState((state) => {
    state.usageEvents.unshift(usage);
    return usage;
  });
}

export async function listProjects(ownerId = DEFAULT_OWNER_ID): Promise<Project[]> {
  const state = await readState();
  return state.projects.filter((project) => project.ownerId === ownerId).sort(sortNewest);
}

async function readState(): Promise<AppState> {
  await ensureRuntimeDirs();
  const path = join(dataDir(), STORE_FILE);
  try {
    return normalizeState(JSON.parse(await readFile(path, "utf8")));
  } catch {
    const state = normalizeState({});
    await writeState(state);
    return state;
  }
}

async function writeState(state: AppState): Promise<void> {
  await ensureRuntimeDirs();
  const path = join(dataDir(), STORE_FILE);
  const temp = `${path}.${createId("tmp")}.tmp`;
  await writeFile(temp, JSON.stringify(normalizeState(state), null, 2));
  await rename(temp, path);
}

async function mutateLocalState<T>(mutator: (state: AppState) => T): Promise<T> {
  const run = localWriteQueue.then(async () => {
    const state = await readState();
    const result = mutator(state);
    await writeState(state);
    return result;
  });
  localWriteQueue = run.catch(() => undefined);
  return run;
}

function normalizeState(raw: Partial<AppState>): AppState {
  return {
    users: raw.users?.length
      ? raw.users
      : [{ id: DEFAULT_OWNER_ID, email: "demo@zhinian.local", displayName: "智念演示用户" }],
    assets: raw.assets || [],
    generationJobs: raw.generationJobs || [],
    usageEvents: raw.usageEvents || [],
    projects: raw.projects || []
  };
}

function getSupabaseAdmin(): SupabaseClient | null {
  const url = process.env.NEXT_PUBLIC_SUPABASE_URL;
  const serviceRoleKey = process.env.SUPABASE_SERVICE_ROLE_KEY;
  if (!url || !serviceRoleKey) return null;
  return createClient(url, serviceRoleKey, {
    auth: { persistSession: false }
  });
}

function sortNewest<T extends { createdAt: string }>(a: T, b: T): number {
  return b.createdAt.localeCompare(a.createdAt);
}

function isClaimableJob(job: GenerationJob, nowIso: string, staleBefore: string): boolean {
  if (["succeeded", "failed", "expired", "cancelled"].includes(job.status)) return false;
  if ((job.scheduledAt || job.createdAt) > nowIso) return false;
  return !job.lockedAt || job.lockedAt < staleBefore;
}

function sortClaimableJobs(a: GenerationJob, b: GenerationJob): number {
  const priority = (b.priority || 0) - (a.priority || 0);
  if (priority !== 0) return priority;
  const scheduled = (a.scheduledAt || a.createdAt).localeCompare(b.scheduledAt || b.createdAt);
  if (scheduled !== 0) return scheduled;
  return a.createdAt.localeCompare(b.createdAt);
}

function assetToRow(asset: Partial<Asset>) {
  return {
    id: asset.id,
    owner_id: asset.ownerId,
    kind: asset.kind,
    name: asset.name,
    url: asset.url,
    storage_path: asset.storagePath,
    source: asset.source,
    tags: asset.tags,
    metadata: asset.metadata,
    created_at: asset.createdAt,
    updated_at: asset.updatedAt
  };
}

function assetFromRow(row: Record<string, unknown>): Asset {
  return {
    id: String(row.id),
    ownerId: String(row.owner_id),
    kind: row.kind as Asset["kind"],
    name: String(row.name),
    url: String(row.url),
    storagePath: row.storage_path ? String(row.storage_path) : undefined,
    source: row.source as Asset["source"],
    tags: Array.isArray(row.tags) ? row.tags.map(String) : [],
    metadata: isRecord(row.metadata) ? row.metadata : {},
    createdAt: String(row.created_at),
    updatedAt: String(row.updated_at)
  };
}

function jobToRow(job: Partial<GenerationJob>) {
  const row: Record<string, unknown> = {};
  if (job.id !== undefined) row.id = job.id;
  if (job.ownerId !== undefined) row.owner_id = job.ownerId;
  if (job.externalClientId !== undefined) row.external_client_id = job.externalClientId;
  if (job.capability !== undefined) row.capability = job.capability;
  if (job.provider !== undefined) row.provider = job.provider;
  if (job.reqKey !== undefined) row.req_key = job.reqKey;
  if (job.status !== undefined) row.status = job.status;
  if (job.prompt !== undefined) row.prompt = job.prompt;
  if (job.inputAssetIds !== undefined) row.input_asset_ids = job.inputAssetIds;
  if (job.inputUrls !== undefined) row.input_urls = job.inputUrls;
  if (job.outputAssetIds !== undefined) row.output_asset_ids = job.outputAssetIds;
  if (job.providerTaskId !== undefined) row.provider_task_id = job.providerTaskId;
  if (job.requestPayload !== undefined) row.request_payload = job.requestPayload;
  if (job.responsePayload !== undefined) row.response_payload = job.responsePayload;
  if (job.error !== undefined) row.error = job.error;
  if (job.retryOf !== undefined) row.retry_of = job.retryOf;
  if (job.idempotencyKey !== undefined) row.idempotency_key = job.idempotencyKey;
  if (job.idempotencyFingerprint !== undefined) row.idempotency_fingerprint = job.idempotencyFingerprint;
  if (job.priority !== undefined) row.priority = job.priority;
  if (job.attempts !== undefined) row.attempts = job.attempts;
  if (job.maxAttempts !== undefined) row.max_attempts = job.maxAttempts;
  if (job.scheduledAt !== undefined) row.scheduled_at = job.scheduledAt;
  if (job.lockedAt !== undefined) row.locked_at = job.lockedAt;
  if (job.lockedBy !== undefined) row.locked_by = job.lockedBy;
  if (job.startedAt !== undefined) row.started_at = job.startedAt;
  if (job.completedAt !== undefined) row.completed_at = job.completedAt;
  if (job.webhookUrl !== undefined) row.webhook_url = job.webhookUrl;
  if (job.webhookAttempts !== undefined) row.webhook_attempts = job.webhookAttempts;
  if (job.webhookLastStatus !== undefined) row.webhook_last_status = job.webhookLastStatus;
  if (job.createdAt !== undefined) row.created_at = job.createdAt;
  if (job.updatedAt !== undefined) row.updated_at = job.updatedAt;
  return row;
}

function jobFromRow(row: Record<string, unknown>): GenerationJob {
  return {
    id: String(row.id),
    ownerId: String(row.owner_id),
    externalClientId: optionalString(row.external_client_id),
    capability: row.capability as GenerationJob["capability"],
    provider: row.provider as GenerationJob["provider"],
    reqKey: String(row.req_key),
    status: row.status as GenerationJob["status"],
    prompt: row.prompt ? String(row.prompt) : undefined,
    inputAssetIds: Array.isArray(row.input_asset_ids) ? row.input_asset_ids.map(String) : [],
    inputUrls: Array.isArray(row.input_urls) ? row.input_urls.map(String) : [],
    outputAssetIds: Array.isArray(row.output_asset_ids) ? row.output_asset_ids.map(String) : [],
    providerTaskId: row.provider_task_id ? String(row.provider_task_id) : undefined,
    requestPayload: isRecord(row.request_payload) ? row.request_payload : {},
    responsePayload: isRecord(row.response_payload) ? row.response_payload : undefined,
    error: isRecord(row.error) ? { message: String(row.error.message || "Unknown error"), code: row.error.code as string | number | undefined, retryable: Boolean(row.error.retryable) } : undefined,
    retryOf: row.retry_of ? String(row.retry_of) : undefined,
    idempotencyKey: optionalString(row.idempotency_key),
    idempotencyFingerprint: optionalString(row.idempotency_fingerprint),
    priority: optionalNumber(row.priority),
    attempts: optionalNumber(row.attempts),
    maxAttempts: optionalNumber(row.max_attempts),
    scheduledAt: optionalString(row.scheduled_at),
    lockedAt: optionalString(row.locked_at),
    lockedBy: optionalString(row.locked_by),
    startedAt: optionalString(row.started_at),
    completedAt: optionalString(row.completed_at),
    webhookUrl: optionalString(row.webhook_url),
    webhookAttempts: optionalNumber(row.webhook_attempts),
    webhookLastStatus: isRecord(row.webhook_last_status)
      ? {
          ok: Boolean(row.webhook_last_status.ok),
          status: optionalNumber(row.webhook_last_status.status),
          error: optionalString(row.webhook_last_status.error),
          attemptedAt: String(row.webhook_last_status.attemptedAt || row.webhook_last_status.attempted_at || ""),
          nextAttemptAt: optionalString(row.webhook_last_status.nextAttemptAt || row.webhook_last_status.next_attempt_at)
        }
      : undefined,
    createdAt: String(row.created_at),
    updatedAt: String(row.updated_at)
  };
}

function usageToRow(usage: UsageEvent) {
  return {
    id: usage.id,
    owner_id: usage.ownerId,
    job_id: usage.jobId,
    capability: usage.capability,
    quantity: usage.quantity,
    estimated_unit: usage.estimatedUnit,
    created_at: usage.createdAt
  };
}

function usageFromRow(row: Record<string, unknown>): UsageEvent {
  return {
    id: String(row.id),
    ownerId: String(row.owner_id),
    jobId: String(row.job_id),
    capability: row.capability as UsageEvent["capability"],
    quantity: Number(row.quantity || 0),
    estimatedUnit: row.estimated_unit as UsageEvent["estimatedUnit"],
    createdAt: String(row.created_at)
  };
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

function optionalString(value: unknown): string | undefined {
  if (typeof value !== "string") return undefined;
  const trimmed = value.trim();
  return trimmed || undefined;
}

function optionalNumber(value: unknown): number | undefined {
  if (value === undefined || value === null || value === "") return undefined;
  const parsed = Number(value);
  return Number.isFinite(parsed) ? parsed : undefined;
}