package server

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"

	"git.lastassault.de/speatzle/morffix/constants"
	"git.lastassault.de/speatzle/morffix/types"
	"github.com/jackc/pgx/v5"
)

type TasksData struct {
	Libraries []Library
	Tasks     []TaskDisplay
}

type TaskDisplay struct {
	ID      int     `db:"id"`
	Library int     `db:"library"`
	Worker  *string `db:"worker"`
	Type    int     `db:"type"`
	Status  string  `db:"status"`
	File    string  `db:"file"`
}

type TaskDB struct {
	ID      int                  `db:"id"`
	Library int                  `db:"library"`
	Worker  *string              `db:"worker"`
	Type    int                  `db:"type"`
	Status  constants.TaskStatus `db:"status"`
	File    string               `db:"file"`
}

func handleTasks(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" {
		err := createTask(r.Context(), r)
		if err != nil {
			slog.ErrorContext(r.Context(), "Create Task", "err", err)
			http.Error(w, "Error Create Library: "+err.Error(), http.StatusInternalServerError)
			return
		}
	}

	data := TasksData{}

	rows, err := db.Query(r.Context(), "SELECT id, name, path, enable FROM libraries WHERE enable = $1", true)
	if err != nil {
		slog.ErrorContext(r.Context(), "Query Libraries", "err", err)
		http.Error(w, "Error Query Libraries: "+err.Error(), http.StatusInternalServerError)
		return
	}
	libraries, err := pgx.CollectRows[Library](rows, pgx.RowToStructByName[Library])
	if err != nil {
		slog.ErrorContext(r.Context(), "Collect Rows", "err", err)
		http.Error(w, "Error Query Libraries: "+err.Error(), http.StatusInternalServerError)
		return
	}
	data.Libraries = libraries

	rows, err = db.Query(r.Context(), "SELECT t.id AS id, l.id AS library, t.worker_id AS worker, t.type AS type, t.status AS status, f.path AS file FROM tasks t INNER JOIN files f ON f.id = t.file_id INNER JOIN libraries l ON l.id = f.library_id ORDER BY CASE t.type WHEN 3 THEN -1 ELSE t.type END, t.id")
	if err != nil {
		slog.ErrorContext(r.Context(), "Query Tasks", "err", err)
		http.Error(w, "Error Query Tasks: "+err.Error(), http.StatusInternalServerError)
		return
	}
	tasks, err := pgx.CollectRows[TaskDB](rows, pgx.RowToStructByName[TaskDB])
	if err != nil {
		slog.ErrorContext(r.Context(), "Collect Tasks", "err", err)
		http.Error(w, "Error Query Tasks: "+err.Error(), http.StatusInternalServerError)
		return
	}
	for i := range tasks {
		data.Tasks = append(data.Tasks, TaskDisplay{
			ID:      tasks[i].ID,
			Library: tasks[i].Library,
			Worker:  tasks[i].Worker,
			Type:    tasks[i].Type,
			File:    tasks[i].File,
			Status:  tasks[i].Status.String(),
		})
	}

	buf := bytes.Buffer{}
	err = templates.ExecuteTemplate(&buf, constants.TASKS_TEMPLATE_NAME, data)
	if err != nil {
		slog.ErrorContext(r.Context(), "Executing Task Template", "err", err)
		http.Error(w, "Error Executing Template: "+err.Error(), http.StatusInternalServerError)
		return
	}

	_, err = w.Write(buf.Bytes())
	if err != nil {
		slog.ErrorContext(r.Context(), "Writing http Response", "err", err)
	}
}

func handleTask(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	if id == "" {
		handleTasks(w, r)
		return
	}

	var log []string
	err := db.QueryRow(r.Context(), "SELECT log FROM tasks WHERE id = $1", id).Scan(&log)
	if err != nil {
		slog.ErrorContext(r.Context(), "Query Tasks", "err", err)
		http.Error(w, "Error Query Tasks: "+err.Error(), http.StatusInternalServerError)
		return
	}

	t := types.Task{
		Log: log,
	}

	buf := bytes.Buffer{}
	err = templates.ExecuteTemplate(&buf, constants.TASK_TEMPLATE_NAME, t)
	if err != nil {
		slog.ErrorContext(r.Context(), "Executing Task Template", "err", err)
		http.Error(w, "Error Executing Template: "+err.Error(), http.StatusInternalServerError)
		return
	}

	_, err = w.Write(buf.Bytes())
	if err != nil {
		slog.ErrorContext(r.Context(), "Writing http Response", "err", err)
	}
}

func createTask(ctx context.Context, r *http.Request) error {
	err := r.ParseForm()
	if err != nil {
		return fmt.Errorf("Parseing Form: %w", err)
	}
	library := r.FormValue("library")
	typ := r.FormValue("type")
	slog.Info("Got Task Create", "library", library, "type", typ)

	rows, err := db.Query(r.Context(), "SELECT id, path, size, status, health, md5 FROM files where library_id = $1 AND status = $2", library, constants.FILE_STATUS_EXISTS)
	if err != nil {
		return fmt.Errorf("Query Files: %w", err)
	}
	files, err := pgx.CollectRows[File](rows, pgx.RowToStructByName[File])
	if err != nil {
		return fmt.Errorf("Collect Files: %w", err)
	}

	tx, err := db.Begin(ctx)
	if err != nil {
		return fmt.Errorf("Begin Transaction: %w", err)
	}
	defer tx.Rollback(ctx)

	var data any
	if true { // TODO typ == constants.TASK_TYPE_HEALTHCHECK {

		// ffmpeg.exe -stats -v error -i "in.mp4" -f null -max_muxing_queue_size 9999 "out.mp4"
		data = types.HealthCheckData{Command: types.FFmpegCommand{
			Args:        []types.Arg{{Flag: "-stats"}, {Flag: "-v", Value: "error"}, {Flag: "-xerror"}},
			InputFiles:  []types.File{{Path: "input.mkv"}},
			OutputFiles: []types.File{{Path: "output.mkv", Arguments: []types.Arg{{Flag: "-f", Value: "null"}, {Flag: "-max_muxing_queue_size", Value: "9999"}}}},
		}}
	}

	for _, file := range files {
		_, err = db.Exec(r.Context(), "INSERT INTO tasks (file_id, type, status, data) VALUES ($1,$2,$3,$4)", file.ID, typ, constants.TASK_STATUS_QUEUED, data)
		if err != nil {
			return fmt.Errorf("Inserting Task: %w", err)
		}
	}

	err = tx.Commit(ctx)
	if err != nil {
		return fmt.Errorf("Committing Transcation: %w", err)
	}

	return nil
}

type QueuedTask struct {
	ID      int
	Type    int
	FileID  int    `json:"file_id"`
	FileMD5 []byte `json:"file_md5" db:"md5"`
	Data    json.RawMessage
}

func assignQueuedTasks(ctx context.Context) error {
	rows, err := db.Query(ctx, "SELECT t.id as id, t.type as type, t.file_id as file_id, f.md5 as md5, t.data as data FROM tasks t INNER JOIN files f ON f.id = t.file_id WHERE t.status = $1", constants.TASK_STATUS_QUEUED)
	if err != nil {
		return fmt.Errorf("Query Queued Tasks: %w", err)
	}
	queuedTasks, err := pgx.CollectRows[QueuedTask](rows, pgx.RowToStructByName[QueuedTask])
	if err != nil {
		return fmt.Errorf("Collect Queued Tasks: %w", err)
	}

	//slog.Info("Assigning Queued Tasks", "count", len(queuedTasks))

	if len(queuedTasks) == 0 {
		return nil
	}

	WorkersMutex.Lock()
	defer WorkersMutex.Unlock()

	lastAssigned := 0

	for i := range Workers {
		if lastAssigned == len(queuedTasks) {
			slog.Info("All Tasks assigned")
			// All Tasks have been Assigned
			return nil
		}
		if Workers[i].Connected {
			var count int
			err := db.QueryRow(ctx, "SELECT COUNT(*) FROM tasks WHERE worker_id = $1 AND (status = $2 OR status = $3 OR status = $4)", i, constants.TASK_STATUS_ASSIGNED, constants.TASK_STATUS_RUNNING, constants.TASK_STATUS_WAITING).Scan(&count)
			if err != nil {
				return fmt.Errorf("Error Querying Worker Task Count: %w", err)
			}

			slog.Info("Assigning Queued Tasks Worker", "worker", i, "count", count)

			// Allow for Multiple Tasks at once in the future
			if count < 1 {
				tx, err := db.Begin(ctx)
				defer tx.Rollback(ctx)
				if err != nil {
					return fmt.Errorf("Starting Transaction: %w", err)
				}
				_, err = tx.Exec(ctx, "UPDATE tasks SET status = $2, worker_id = $3 WHERE id = $1", queuedTasks[lastAssigned].ID, constants.TASK_STATUS_ASSIGNED, i)
				if err != nil {
					return fmt.Errorf("Setting tasks Assignment: %w", err)
				}

				taskStart := types.TaskStart{
					ID:      queuedTasks[lastAssigned].ID,
					Type:    queuedTasks[lastAssigned].Type,
					FileID:  queuedTasks[lastAssigned].FileID,
					FileMD5: queuedTasks[lastAssigned].FileMD5,
					Data:    queuedTasks[lastAssigned].Data,
				}

				_, err = rpcServer.Call(ctx, Workers[i].Conn, "task-start", taskStart, nil)
				if err != nil {
					return fmt.Errorf("Error Starting Task: %w", err)
				}

				err = tx.Commit(ctx)
				if err != nil {
					return fmt.Errorf("Error Committing Transaction: %w", err)
				}

				slog.InfoContext(ctx, "Assigned Task to Worker", "task", queuedTasks[lastAssigned].ID, "worker", i)
				lastAssigned++
			}
		}
	}
	return nil
}