"""Task scheduler with heartbeat, ClickUp polling, and folder watch support."""

from __future__ import annotations

import contextlib
import json
import logging
import re
import shutil
import threading
from datetime import UTC, datetime
from pathlib import Path
from typing import TYPE_CHECKING

from croniter import croniter

if TYPE_CHECKING:
    from .agent import Agent
    from .config import Config
    from .db import Database
    from .notifications import NotificationBus

log = logging.getLogger(__name__)

HEARTBEAT_OK = "HEARTBEAT_OK"

# Matches **Docx:** `path/to/file.docx` patterns in tool output
_DOCX_PATH_RE = re.compile(r"\*\*Docx:\*\*\s*`([^`]+\.docx)`")


def _extract_docx_paths(result: str) -> list[str]:
    """Extract .docx file paths from a tool result string."""
    return _DOCX_PATH_RE.findall(result)


class Scheduler:
    # Tasks due within this window are eligible for execution
    DUE_DATE_WINDOW_WEEKS = 3

    def __init__(
        self,
        config: Config,
        db: Database,
        agent: Agent,
        notification_bus: NotificationBus | None = None,
    ):
        self.config = config
        self.db = db
        self.agent = agent
        self.notification_bus = notification_bus
        self._stop_event = threading.Event()
        self._thread: threading.Thread | None = None
        self._heartbeat_thread: threading.Thread | None = None
        self._clickup_thread: threading.Thread | None = None
        self._folder_watch_thread: threading.Thread | None = None
        self._clickup_client = None
        self._field_filter_cache: dict | None = None

    def start(self):
        """Start the scheduler, heartbeat, and ClickUp threads."""
        self._thread = threading.Thread(target=self._poll_loop, daemon=True, name="scheduler")
        self._thread.start()

        self._heartbeat_thread = threading.Thread(
            target=self._heartbeat_loop, daemon=True, name="heartbeat"
        )
        self._heartbeat_thread.start()

        # Start ClickUp polling if configured
        if self.config.clickup.enabled:
            self._clickup_thread = threading.Thread(
                target=self._clickup_loop, daemon=True, name="clickup"
            )
            self._clickup_thread.start()
            log.info(
                "ClickUp polling started (interval=%dm)", self.config.clickup.poll_interval_minutes
            )
        else:
            log.info("ClickUp integration disabled (no API token)")

        # Start folder watcher if configured
        watch_folder = self.config.link_building.watch_folder
        if watch_folder:
            self._folder_watch_thread = threading.Thread(
                target=self._folder_watch_loop, daemon=True, name="folder-watch"
            )
            self._folder_watch_thread.start()
            log.info(
                "Folder watcher started (folder=%s, interval=%dm)",
                watch_folder,
                self.config.link_building.watch_interval_minutes,
            )
        else:
            log.info("Folder watcher disabled (no watch_folder configured)")

        log.info(
            "Scheduler started (poll=%ds, heartbeat=%dm)",
            self.config.scheduler.poll_interval_seconds,
            self.config.scheduler.heartbeat_interval_minutes,
        )

    def stop(self):
        self._stop_event.set()
        if self._clickup_client:
            self._clickup_client.close()

    def _notify(self, message: str, category: str = "clickup"):
        """Push a notification through the bus if available."""
        if self.notification_bus:
            self.notification_bus.push(message, category)
        else:
            log.info("Notification [%s]: %s", category, message)

    # ── Scheduled Tasks ──

    def _poll_loop(self):
        while not self._stop_event.is_set():
            try:
                self._run_due_tasks()
            except Exception as e:
                log.error("Scheduler poll error: %s", e)
            self._stop_event.wait(self.config.scheduler.poll_interval_seconds)

    def _run_due_tasks(self):
        tasks = self.db.get_due_tasks()
        for task in tasks:
            try:
                log.info("Running scheduled task: %s", task["name"])
                result = self.agent.execute_task(task["prompt"])
                self.db.log_task_run(task["id"], result=result[:2000])

                # Calculate next run
                schedule = task["schedule"]
                if schedule.startswith("once:"):
                    # One-time task, disable it
                    self.db.disable_task(task["id"])
                else:
                    # Cron schedule - calculate next run
                    now = datetime.now(UTC)
                    cron = croniter(schedule, now)
                    next_run = cron.get_next(datetime)
                    self.db.update_task_next_run(task["id"], next_run.isoformat())
            except Exception as e:
                log.error("Task '%s' failed: %s", task["name"], e)
                self.db.log_task_run(task["id"], error=str(e))

    # ── Heartbeat ──

    def _heartbeat_loop(self):
        interval = self.config.scheduler.heartbeat_interval_minutes * 60
        # Wait a bit before first heartbeat
        self._stop_event.wait(60)

        while not self._stop_event.is_set():
            try:
                self._run_heartbeat()
            except Exception as e:
                log.error("Heartbeat error: %s", e)
            self._stop_event.wait(interval)

    def _run_heartbeat(self):
        heartbeat_path = self.config.identity_dir / "HEARTBEAT.md"
        if not heartbeat_path.exists():
            return

        checklist = heartbeat_path.read_text(encoding="utf-8")
        prompt = (
            f"HEARTBEAT CHECK. Review this checklist and take action if needed.\n"
            f"If nothing needs attention, respond with exactly: {HEARTBEAT_OK}\n\n"
            f"{checklist}"
        )

        result = self.agent.execute_task(prompt, system_context=checklist)

        if HEARTBEAT_OK in result:
            log.debug("Heartbeat: all clear")
        else:
            log.info("Heartbeat action taken: %s", result[:200])

    # ── ClickUp Integration ──

    def _get_clickup_client(self):
        """Lazy-init the ClickUp API client."""
        if self._clickup_client is None:
            from .clickup import ClickUpClient

            self._clickup_client = ClickUpClient(
                api_token=self.config.clickup.api_token,
                workspace_id=self.config.clickup.workspace_id,
                task_type_field_name=self.config.clickup.task_type_field_name,
            )
        return self._clickup_client

    def _clickup_loop(self):
        """Poll ClickUp for tasks on a regular interval."""
        interval = self.config.clickup.poll_interval_minutes * 60

        # Wait before first poll to let other systems initialize
        self._stop_event.wait(30)

        while not self._stop_event.is_set():
            try:
                self._poll_clickup()
            except Exception as e:
                log.error("ClickUp poll error: %s", e)
            self._stop_event.wait(interval)

    def _discover_field_filter(self, client):
        """Discover and cache the Work Category field UUID + option map."""
        space_id = self.config.clickup.space_id
        list_ids = client.get_list_ids_from_space(space_id)
        if not list_ids:
            log.warning("No lists found in space %s — cannot discover field filter", space_id)
            return None

        # Use the first list to discover field metadata
        first_list = next(iter(list_ids))
        field_name = self.config.clickup.task_type_field_name
        result = client.discover_field_filter(first_list, field_name)
        if result:
            log.info(
                "Discovered field filter for '%s': field_id=%s, options=%s",
                field_name,
                result["field_id"],
                list(result["options"].keys()),
            )
        else:
            log.warning(
                "Field '%s' not found in list %s — falling back to client-side filtering",
                field_name,
                first_list,
            )
        return result

    def _poll_clickup(self):
        """Poll ClickUp for eligible tasks and execute them immediately."""
        client = self._get_clickup_client()
        space_id = self.config.clickup.space_id
        if not space_id:
            log.warning("ClickUp space_id not configured, skipping poll")
            return

        skill_map = self.config.clickup.skill_map
        if not skill_map:
            log.debug("No skill_map configured, skipping ClickUp poll")
            return

        # Discover field filter on first poll
        if self._field_filter_cache is None:
            self._field_filter_cache = self._discover_field_filter(client) or {}

        # Build API filters
        now_ms = int(datetime.now(UTC).timestamp() * 1000)
        due_date_lt = now_ms + (self.DUE_DATE_WINDOW_WEEKS * 7 * 24 * 60 * 60 * 1000)

        custom_fields_filter = None
        if self._field_filter_cache and self._field_filter_cache.get("options"):
            field_id = self._field_filter_cache["field_id"]
            options = self._field_filter_cache["options"]
            # Only include options that map to skills we have
            matching_opt_ids = [options[name] for name in skill_map if name in options]
            if matching_opt_ids:
                import json as _json

                custom_fields_filter = _json.dumps(
                    [{"field_id": field_id, "operator": "ANY", "value": matching_opt_ids}]
                )

        tasks = client.get_tasks_from_space(
            space_id,
            statuses=self.config.clickup.poll_statuses,
            due_date_lt=due_date_lt,
            custom_fields=custom_fields_filter,
        )

        for task in tasks:
            # Skip tasks already processed in kv_store
            raw = self.db.kv_get(f"clickup:task:{task.id}:state")
            if raw:
                try:
                    existing = json.loads(raw)
                    if existing.get("state") in ("executing", "completed", "failed"):
                        continue
                except json.JSONDecodeError:
                    pass

            # Client-side verify: Work Category must be in skill_map
            if task.task_type not in skill_map:
                continue

            # Respect auto_execute flag — skip tasks that require manual trigger
            mapping = skill_map[task.task_type]
            if not mapping.get("auto_execute", False):
                log.debug(
                    "Skipping task '%s' (type=%s): auto_execute is false",
                    task.name,
                    task.task_type,
                )
                continue

            # Client-side verify: due_date must exist and be within window
            if not task.due_date:
                continue
            try:
                task_due_ms = int(task.due_date)
                if task_due_ms > due_date_lt:
                    continue
            except (ValueError, TypeError):
                continue

            self._execute_task(task)

    def _execute_task(self, task):
        """Execute a single ClickUp task immediately."""
        skill_map = self.config.clickup.skill_map
        mapping = skill_map.get(task.task_type, {})
        tool_name = mapping.get("tool", "")
        if not tool_name:
            log.warning("No tool in skill_map for type '%s'", task.task_type)
            return

        task_id = task.id
        kv_key = f"clickup:task:{task_id}:state"
        now = datetime.now(UTC).isoformat()
        client = self._get_clickup_client()

        # Build state object — starts at "executing"
        state = {
            "state": "executing",
            "clickup_task_id": task_id,
            "clickup_task_name": task.name,
            "task_type": task.task_type,
            "skill_name": tool_name,
            "discovered_at": now,
            "started_at": now,
            "completed_at": None,
            "error": None,
            "deliverable_paths": [],
            "custom_fields": task.custom_fields,
        }

        # Move to "automation underway" on ClickUp immediately
        client.update_task_status(task_id, self.config.clickup.automation_status)
        self.db.kv_set(kv_key, json.dumps(state))

        log.info("Executing ClickUp task: %s → %s", task.name, tool_name)
        self._notify(f"Executing ClickUp task: **{task.name}** → Skill: `{tool_name}`")

        try:
            # Build tool arguments from field mapping
            args = self._build_tool_args(state)
            args["clickup_task_id"] = task_id

            # Execute the skill via the tool registry
            if hasattr(self.agent, "_tools") and self.agent._tools:
                result = self.agent._tools.execute(tool_name, args)
            else:
                result = self.agent.execute_task(
                    f"Execute the '{tool_name}' tool for ClickUp task '{task.name}'. "
                    f"Task description: {state.get('custom_fields', {})}"
                )

            # Check if the tool skipped or reported an error without doing work
            if result.startswith("Skipped:") or result.startswith("Error:"):
                state["state"] = "failed"
                state["error"] = result[:500]
                state["completed_at"] = datetime.now(UTC).isoformat()
                self.db.kv_set(kv_key, json.dumps(state))

                client.add_comment(
                    task_id,
                    f"⚠️ CheddahBot could not execute this task.\n\n{result[:2000]}",
                )
                # Move to "error" so Bryan can see what happened
                client.update_task_status(task_id, self.config.clickup.error_status)

                self._notify(
                    f"ClickUp task skipped: **{task.name}**\n"
                    f"Reason: {result[:200]}"
                )
                log.info("ClickUp task skipped: %s — %s", task.name, result[:200])
                return

            # Check if the tool already handled ClickUp sync internally
            tool_handled_sync = "## ClickUp Sync" in result

            if tool_handled_sync:
                state["state"] = "completed"
                state["completed_at"] = datetime.now(UTC).isoformat()
                self.db.kv_set(kv_key, json.dumps(state))
            else:
                # Scheduler handles sync (fallback path)
                docx_paths = _extract_docx_paths(result)
                state["deliverable_paths"] = docx_paths
                uploaded_count = 0
                for path in docx_paths:
                    if client.upload_attachment(task_id, path):
                        uploaded_count += 1
                    else:
                        log.warning("Failed to upload %s for task %s", path, task_id)

                state["state"] = "completed"
                state["completed_at"] = datetime.now(UTC).isoformat()
                self.db.kv_set(kv_key, json.dumps(state))

                client.update_task_status(task_id, self.config.clickup.review_status)
                attach_note = f"\n📎 {uploaded_count} file(s) attached." if uploaded_count else ""
                comment = (
                    f"✅ CheddahBot completed this task.\n\n"
                    f"Skill: {tool_name}\n"
                    f"Result:\n{result[:3000]}{attach_note}"
                )
                client.add_comment(task_id, comment)

            self._notify(
                f"ClickUp task completed: **{task.name}**\n"
                f"Skill: `{tool_name}` | Status set to '{self.config.clickup.review_status}'"
            )
            log.info("ClickUp task completed: %s", task.name)

        except Exception as e:
            # Failure — move back to "to do" on ClickUp
            state["state"] = "failed"
            state["error"] = str(e)
            state["completed_at"] = datetime.now(UTC).isoformat()
            self.db.kv_set(kv_key, json.dumps(state))

            client.add_comment(
                task_id, f"❌ CheddahBot failed to complete this task.\n\nError: {str(e)[:2000]}"
            )
            # Move to "error" so Bryan can see what happened
            client.update_task_status(task_id, self.config.clickup.error_status)

            self._notify(
                f"ClickUp task failed: **{task.name}**\n"
                f"Skill: `{tool_name}` | Error: {str(e)[:200]}"
            )
            log.error("ClickUp task failed: %s — %s", task.name, e)

    def _build_tool_args(self, state: dict) -> dict:
        """Build tool arguments from ClickUp task fields using the field mapping."""
        skill_map = self.config.clickup.skill_map
        task_type = state.get("task_type", "")
        mapping = skill_map.get(task_type, {})
        field_mapping = mapping.get("field_mapping", {})

        args = {}
        for tool_param, source in field_mapping.items():
            if source == "task_name":
                args[tool_param] = state.get("clickup_task_name", "")
            elif source == "task_description":
                args[tool_param] = state.get("custom_fields", {}).get("description", "")
            else:
                # Look up custom field by name
                args[tool_param] = state.get("custom_fields", {}).get(source, "")

        return args

    # ── Folder Watcher ──

    def _folder_watch_loop(self):
        """Poll the watch folder for new .xlsx files on a regular interval."""
        interval = self.config.link_building.watch_interval_minutes * 60

        # Wait before first scan to let other systems initialize
        self._stop_event.wait(60)

        while not self._stop_event.is_set():
            try:
                self._scan_watch_folder()
            except Exception as e:
                log.error("Folder watcher error: %s", e)
            self._stop_event.wait(interval)

    def _scan_watch_folder(self):
        """Scan the watch folder for new .xlsx files and match to ClickUp tasks."""
        watch_folder = Path(self.config.link_building.watch_folder)
        if not watch_folder.exists():
            log.warning("Watch folder does not exist: %s", watch_folder)
            return

        xlsx_files = sorted(watch_folder.glob("*.xlsx"))
        if not xlsx_files:
            log.debug("No .xlsx files in watch folder")
            return

        for xlsx_path in xlsx_files:
            filename = xlsx_path.name
            # Skip Office temp/lock files (e.g. ~$insert_molding.xlsx)
            if filename.startswith("~$"):
                continue
            kv_key = f"linkbuilding:watched:{filename}"

            # Skip completed/failed; retry "processing" (killed run) and "blocked" (missing field)
            existing = self.db.kv_get(kv_key)
            if existing:
                try:
                    state = json.loads(existing)
                    if state.get("status") in ("completed", "failed"):
                        continue
                    if state.get("status") in ("processing", "blocked", "unmatched"):
                        log.info("Retrying '%s' state for %s", state["status"], filename)
                        self.db.kv_delete(kv_key)
                except json.JSONDecodeError:
                    continue

            log.info("Folder watcher: new .xlsx found: %s", filename)
            self._process_watched_file(xlsx_path, kv_key)

    def _process_watched_file(self, xlsx_path: Path, kv_key: str):
        """Try to match a watched .xlsx file to a ClickUp task and run the pipeline."""
        filename = xlsx_path.name
        # Normalize filename stem for matching
        # e.g., "precision-cnc-machining" → "precision cnc machining"
        stem = xlsx_path.stem.lower().replace("-", " ").replace("_", " ")
        stem = re.sub(r"\s+", " ", stem).strip()

        # Mark as processing
        self.db.kv_set(
            kv_key,
            json.dumps({"status": "processing", "started_at": datetime.now(UTC).isoformat()}),
        )

        # Try to find matching ClickUp task
        matched_task = None
        if self.config.clickup.enabled:
            matched_task = self._match_xlsx_to_clickup(stem)

        if not matched_task:
            log.warning("No ClickUp task match for '%s' — skipping", filename)
            self.db.kv_set(
                kv_key,
                json.dumps(
                    {
                        "status": "unmatched",
                        "filename": filename,
                        "stem": stem,
                        "checked_at": datetime.now(UTC).isoformat(),
                    }
                ),
            )
            self._notify(
                f"Folder watcher: no ClickUp match for **{filename}**.\n"
                f"Create a Link Building task with Keyword "
                f"matching '{stem}' to enable auto-processing.",
                category="linkbuilding",
            )
            return

        # Extract tool args from matched task
        task_id = matched_task.id
        log.info("Matched '%s' to ClickUp task %s (%s)", filename, task_id, matched_task.name)

        # Set ClickUp status to "automation underway"
        client = self._get_clickup_client()
        client.update_task_status(task_id, self.config.clickup.automation_status)

        self._notify(
            f"Folder watcher: matched **{filename}** to ClickUp task **{matched_task.name}**.\n"
            f"Starting Cora Backlinks pipeline...",
            category="linkbuilding",
        )

        # Build tool args from the matched task's custom fields
        money_site_url = matched_task.custom_fields.get("IMSURL", "") or ""
        if not money_site_url:
            log.warning("Task %s (%s) missing IMSURL — skipping", task_id, matched_task.name)
            self.db.kv_set(
                kv_key,
                json.dumps(
                    {
                        "status": "blocked",
                        "reason": "missing_imsurl",
                        "filename": filename,
                        "task_id": task_id,
                        "task_name": matched_task.name,
                        "checked_at": datetime.now(UTC).isoformat(),
                    }
                ),
            )
            # Set ClickUp status to "error" so it's visible on the board
            client.update_task_status(task_id, self.config.clickup.error_status)
            self._notify(
                f"Folder watcher: **{filename}** matched task **{matched_task.name}** "
                f"but **IMSURL is empty**. Set the IMSURL field in ClickUp before "
                f"the file can be processed.",
                category="linkbuilding",
            )
            return

        args = {
            "xlsx_path": str(xlsx_path),
            "project_name": matched_task.name,
            "money_site_url": money_site_url,
            "custom_anchors": matched_task.custom_fields.get("CustomAnchors", "") or "",
            "cli_flags": matched_task.custom_fields.get("CLIFlags", "") or "",
            "clickup_task_id": task_id,
        }

        # Parse branded_plus_ratio
        bp_raw = matched_task.custom_fields.get("BrandedPlusRatio", "")
        if bp_raw:
            with contextlib.suppress(ValueError, TypeError):
                args["branded_plus_ratio"] = float(bp_raw)

        try:
            # Execute via tool registry
            if hasattr(self.agent, "_tools") and self.agent._tools:
                result = self.agent._tools.execute("run_cora_backlinks", args)
            else:
                result = "Error: tool registry not available"

            if "Error" in result and "## Step" not in result:
                # Pipeline failed
                self.db.kv_set(
                    kv_key,
                    json.dumps(
                        {
                            "status": "failed",
                            "filename": filename,
                            "task_id": task_id,
                            "error": result[:500],
                            "failed_at": datetime.now(UTC).isoformat(),
                        }
                    ),
                )
                client.update_task_status(task_id, self.config.clickup.error_status)
                self._notify(
                    f"Folder watcher: pipeline **failed** for **{filename}**.\n"
                    f"Error: {result[:200]}",
                    category="linkbuilding",
                )
            else:
                # Success — move file to processed/
                processed_dir = xlsx_path.parent / "processed"
                processed_dir.mkdir(exist_ok=True)
                dest = processed_dir / filename
                try:
                    shutil.move(str(xlsx_path), str(dest))
                    log.info("Moved %s to %s", filename, dest)
                except OSError as e:
                    log.warning("Could not move %s to processed: %s", filename, e)

                self.db.kv_set(
                    kv_key,
                    json.dumps(
                        {
                            "status": "completed",
                            "filename": filename,
                            "task_id": task_id,
                            "completed_at": datetime.now(UTC).isoformat(),
                        }
                    ),
                )
                client.update_task_status(task_id, "complete")
                self._notify(
                    f"Folder watcher: pipeline **completed** for **{filename}**.\n"
                    f"ClickUp task: {matched_task.name}",
                    category="linkbuilding",
                )

        except Exception as e:
            log.error("Folder watcher pipeline error for %s: %s", filename, e)
            self.db.kv_set(
                kv_key,
                json.dumps(
                    {
                        "status": "failed",
                        "filename": filename,
                        "task_id": task_id,
                        "error": str(e)[:500],
                        "failed_at": datetime.now(UTC).isoformat(),
                    }
                ),
            )
            client.update_task_status(task_id, self.config.clickup.error_status)

    def _match_xlsx_to_clickup(self, normalized_stem: str):
        """Find a ClickUp Link Building task whose Keyword matches the file stem.

        Returns the matched ClickUpTask or None.
        """
        from .tools.linkbuilding import _fuzzy_keyword_match, _normalize_for_match

        client = self._get_clickup_client()
        space_id = self.config.clickup.space_id
        if not space_id:
            return None

        try:
            tasks = client.get_tasks_from_overall_lists(space_id)
        except Exception as e:
            log.warning("ClickUp query failed in _match_xlsx_to_clickup: %s", e)
            return None

        for task in tasks:
            if task.task_type != "Link Building":
                continue

            lb_method = task.custom_fields.get("LB Method", "")
            if lb_method and lb_method != "Cora Backlinks":
                continue

            keyword = task.custom_fields.get("Keyword", "")
            if not keyword:
                continue

            keyword_norm = _normalize_for_match(str(keyword))
            if _fuzzy_keyword_match(normalized_stem, keyword_norm):
                return task

        return None