"""Crawl job management + trigger endpoints."""

import asyncio
import json
import os
import uuid
from datetime import datetime, timezone
from fastapi import APIRouter, HTTPException, Header, BackgroundTasks
from pydantic import BaseModel

from db import get_pool
from config import settings
from crawlers.filesystem_crawler import FilesystemCrawler
from extractors.dispatcher import extract_text
from classifiers.llm_classifier import classify_document

router = APIRouter(tags=["jobs"])


class JobCreate(BaseModel):
    source_id: str
    job_type: str = "full"  # full or delta


async def _run_crawl_job(job_id: str, source_id: str, tenant_id: str, job_type: str):
    """Background task that executes a crawl job."""
    pool = await get_pool()

    async with pool.acquire() as conn:
        source = await conn.fetchrow(
            "SELECT * FROM crawler_sources WHERE id = $1", uuid.UUID(source_id)
        )
        if not source:
            await conn.execute(
                "UPDATE crawler_jobs SET status = 'failed', error_message = 'Source not found', completed_at = NOW() WHERE id = $1",
                uuid.UUID(job_id),
            )
            return

        # Mark job as running
        await conn.execute(
            "UPDATE crawler_jobs SET status = 'running', started_at = NOW() WHERE id = $1",
            uuid.UUID(job_id),
        )

    # Resolve path
    source_path = source["path"]
    if not os.path.isabs(source_path):
        source_path = os.path.join(settings.CRAWL_BASE_PATH, source_path)

    exts = json.loads(source["file_extensions"]) if isinstance(source["file_extensions"], str) else source["file_extensions"]
    excludes = json.loads(source["exclude_patterns"]) if isinstance(source["exclude_patterns"], str) else source["exclude_patterns"]

    crawler = FilesystemCrawler(
        base_path=source_path,
        file_extensions=exts,
        max_depth=source["max_depth"],
        exclude_patterns=excludes,
    )

    files = crawler.crawl()

    stats = {
        "files_found": len(files),
        "files_processed": 0,
        "files_new": 0,
        "files_changed": 0,
        "files_skipped": 0,
        "files_error": 0,
    }

    for crawled in files:
        try:
            async with pool.acquire() as conn:
                # Check for existing document (delta detection)
                existing = await conn.fetchrow(
                    "SELECT id, file_hash FROM crawler_documents WHERE tenant_id = $1 AND source_id = $2 AND file_path = $3",
                    uuid.UUID(tenant_id), uuid.UUID(source_id), crawled.file_path,
                )

                if existing:
                    if job_type == "delta" and existing["file_hash"] == crawled.file_hash:
                        # Unchanged — skip
                        await conn.execute(
                            "UPDATE crawler_documents SET last_seen_at = NOW() WHERE id = $1",
                            existing["id"],
                        )
                        stats["files_skipped"] += 1
                        stats["files_processed"] += 1
                        continue
                    elif existing["file_hash"] != crawled.file_hash:
                        stats["files_changed"] += 1
                    else:
                        stats["files_skipped"] += 1
                        stats["files_processed"] += 1
                        continue
                else:
                    stats["files_new"] += 1

                # Extract text
                extraction_status = "completed"
                extracted_text = ""
                try:
                    extracted_text = extract_text(crawled.file_path, crawled.file_extension)
                except Exception:
                    extraction_status = "failed"

                # Classify
                classification_result = {"classification": None, "confidence": None, "reasoning": None}
                if extracted_text:
                    classification_result = await classify_document(
                        extracted_text, crawled.file_name, tenant_id
                    )

                if existing:
                    # Update existing
                    await conn.execute(
                        """UPDATE crawler_documents SET
                            job_id = $1, file_size_bytes = $2, file_hash = $3,
                            extracted_text = $4, extraction_status = $5,
                            classification = $6, classification_confidence = $7,
                            classification_reasoning = $8, classification_corrected = false,
                            last_seen_at = NOW(), version_count = version_count + 1,
                            updated_at = NOW()
                        WHERE id = $9""",
                        uuid.UUID(job_id), crawled.file_size_bytes, crawled.file_hash,
                        extracted_text, extraction_status,
                        classification_result["classification"],
                        classification_result["confidence"],
                        classification_result["reasoning"],
                        existing["id"],
                    )
                else:
                    # Insert new
                    await conn.execute(
                        """INSERT INTO crawler_documents
                           (tenant_id, source_id, job_id, file_path, file_name, file_extension,
                            file_size_bytes, file_hash, extracted_text, extraction_status,
                            classification, classification_confidence, classification_reasoning)
                           VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13)""",
                        uuid.UUID(tenant_id), uuid.UUID(source_id), uuid.UUID(job_id),
                        crawled.file_path, crawled.file_name, crawled.file_extension,
                        crawled.file_size_bytes, crawled.file_hash,
                        extracted_text, extraction_status,
                        classification_result["classification"],
                        classification_result["confidence"],
                        classification_result["reasoning"],
                    )

                stats["files_processed"] += 1

        except Exception:
            stats["files_error"] += 1
            stats["files_processed"] += 1

        # Update job progress
        async with pool.acquire() as conn:
            await conn.execute(
                """UPDATE crawler_jobs SET
                    files_found=$2, files_processed=$3, files_new=$4,
                    files_changed=$5, files_skipped=$6, files_error=$7
                WHERE id = $1""",
                uuid.UUID(job_id),
                stats["files_found"], stats["files_processed"],
                stats["files_new"], stats["files_changed"],
                stats["files_skipped"], stats["files_error"],
            )

    # Mark completed
    async with pool.acquire() as conn:
        await conn.execute(
            "UPDATE crawler_jobs SET status = 'completed', completed_at = NOW() WHERE id = $1",
            uuid.UUID(job_id),
        )


@router.post("/jobs", status_code=201)
async def create_job(
    body: JobCreate,
    background_tasks: BackgroundTasks,
    x_tenant_id: str = Header(...),
):
    pool = await get_pool()
    async with pool.acquire() as conn:
        # Verify source exists
        source = await conn.fetchrow(
            "SELECT id FROM crawler_sources WHERE id = $1 AND tenant_id = $2",
            uuid.UUID(body.source_id), uuid.UUID(x_tenant_id),
        )
        if not source:
            raise HTTPException(404, "Source not found")

        # Check no job already running for this source
        running = await conn.fetchval(
            "SELECT EXISTS(SELECT 1 FROM crawler_jobs WHERE source_id = $1 AND status = 'running')",
            uuid.UUID(body.source_id),
        )
        if running:
            raise HTTPException(409, "A job is already running for this source")

        row = await conn.fetchrow(
            """INSERT INTO crawler_jobs (tenant_id, source_id, job_type)
               VALUES ($1, $2, $3) RETURNING *""",
            uuid.UUID(x_tenant_id), uuid.UUID(body.source_id), body.job_type,
        )

    job_id = str(row["id"])
    background_tasks.add_task(_run_crawl_job, job_id, body.source_id, x_tenant_id, body.job_type)

    return dict(row)


@router.get("/jobs")
async def list_jobs(x_tenant_id: str = Header(...)):
    pool = await get_pool()
    async with pool.acquire() as conn:
        rows = await conn.fetch(
            """SELECT j.*, s.name as source_name
               FROM crawler_jobs j JOIN crawler_sources s ON j.source_id = s.id
               WHERE j.tenant_id = $1 ORDER BY j.created_at DESC LIMIT 50""",
            uuid.UUID(x_tenant_id),
        )
    return [dict(r) for r in rows]


@router.get("/jobs/{job_id}")
async def get_job(job_id: str, x_tenant_id: str = Header(...)):
    pool = await get_pool()
    async with pool.acquire() as conn:
        row = await conn.fetchrow(
            "SELECT * FROM crawler_jobs WHERE id = $1 AND tenant_id = $2",
            uuid.UUID(job_id), uuid.UUID(x_tenant_id),
        )
    if not row:
        raise HTTPException(404, "Job not found")
    return dict(row)


@router.post("/jobs/{job_id}/cancel")
async def cancel_job(job_id: str, x_tenant_id: str = Header(...)):
    pool = await get_pool()
    async with pool.acquire() as conn:
        result = await conn.execute(
            "UPDATE crawler_jobs SET status = 'cancelled', completed_at = NOW() WHERE id = $1 AND tenant_id = $2 AND status IN ('pending', 'running')",
            uuid.UUID(job_id), uuid.UUID(x_tenant_id),
        )
    if result == "UPDATE 0":
        raise HTTPException(404, "Job not found or not cancellable")
    return {"status": "cancelled"}