package diunwebhook

import (
	"database/sql"
	"encoding/json"
	"log"
	"net/http"
	"strconv"
	"strings"
	"sync"
	"time"

	_ "modernc.org/sqlite"
)

type DiunEvent struct {
	DiunVersion string    `json:"diun_version"`
	Hostname    string    `json:"hostname"`
	Status      string    `json:"status"`
	Provider    string    `json:"provider"`
	Image       string    `json:"image"`
	HubLink     string    `json:"hub_link"`
	MimeType    string    `json:"mime_type"`
	Digest      string    `json:"digest"`
	Created     time.Time `json:"created"`
	Platform    string    `json:"platform"`
	Metadata    struct {
		ContainerName string `json:"ctn_names"`
		ContainerID   string `json:"ctn_id"`
		State         string `json:"ctn_state"`
		Status        string `json:"ctn_status"`
	} `json:"metadata"`
}

type Tag struct {
	ID   int    `json:"id"`
	Name string `json:"name"`
}

type UpdateEntry struct {
	Event        DiunEvent `json:"event"`
	ReceivedAt   time.Time `json:"received_at"`
	Acknowledged bool      `json:"acknowledged"`
	Tag          *Tag      `json:"tag"`
}

var (
	mu sync.Mutex
	db *sql.DB
)

func InitDB(path string) error {
	var err error
	db, err = sql.Open("sqlite", path)
	if err != nil {
		return err
	}
	db.SetMaxOpenConns(1)
	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS updates (
		image           TEXT PRIMARY KEY,
		diun_version    TEXT NOT NULL DEFAULT '',
		hostname        TEXT NOT NULL DEFAULT '',
		status          TEXT NOT NULL DEFAULT '',
		provider        TEXT NOT NULL DEFAULT '',
		hub_link        TEXT NOT NULL DEFAULT '',
		mime_type       TEXT NOT NULL DEFAULT '',
		digest          TEXT NOT NULL DEFAULT '',
		created         TEXT NOT NULL DEFAULT '',
		platform        TEXT NOT NULL DEFAULT '',
		ctn_name        TEXT NOT NULL DEFAULT '',
		ctn_id          TEXT NOT NULL DEFAULT '',
		ctn_state       TEXT NOT NULL DEFAULT '',
		ctn_status      TEXT NOT NULL DEFAULT '',
		received_at     TEXT NOT NULL,
		acknowledged_at TEXT
	)`)
	if err != nil {
		return err
	}
	// Migration: add acknowledged_at to existing databases (silently ignored if already present)
	_, _ = db.Exec(`ALTER TABLE updates ADD COLUMN acknowledged_at TEXT`)

	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS tags (
		id   INTEGER PRIMARY KEY AUTOINCREMENT,
		name TEXT NOT NULL UNIQUE
	)`)
	if err != nil {
		return err
	}
	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS tag_assignments (
		image  TEXT PRIMARY KEY,
		tag_id INTEGER NOT NULL REFERENCES tags(id) ON DELETE CASCADE
	)`)
	if err != nil {
		return err
	}
	return nil
}

func UpdateEvent(event DiunEvent) error {
	mu.Lock()
	defer mu.Unlock()
	_, err := db.Exec(`INSERT OR REPLACE INTO updates VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,NULL)`,
		event.Image, event.DiunVersion, event.Hostname, event.Status, event.Provider,
		event.HubLink, event.MimeType, event.Digest,
		event.Created.Format(time.RFC3339), event.Platform,
		event.Metadata.ContainerName, event.Metadata.ContainerID,
		event.Metadata.State, event.Metadata.Status,
		time.Now().Format(time.RFC3339),
	)
	return err
}

func GetUpdates() (map[string]UpdateEntry, error) {
	rows, err := db.Query(`SELECT u.image, u.diun_version, u.hostname, u.status, u.provider,
		u.hub_link, u.mime_type, u.digest, u.created, u.platform,
		u.ctn_name, u.ctn_id, u.ctn_state, u.ctn_status, u.received_at, COALESCE(u.acknowledged_at, ''),
		t.id, t.name
		FROM updates u
		LEFT JOIN tag_assignments ta ON u.image = ta.image
		LEFT JOIN tags t             ON ta.tag_id = t.id`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	result := make(map[string]UpdateEntry)
	for rows.Next() {
		var e UpdateEntry
		var createdStr, receivedStr, acknowledgedAt string
		var tagID sql.NullInt64
		var tagName sql.NullString
		err := rows.Scan(&e.Event.Image, &e.Event.DiunVersion, &e.Event.Hostname,
			&e.Event.Status, &e.Event.Provider, &e.Event.HubLink, &e.Event.MimeType,
			&e.Event.Digest, &createdStr, &e.Event.Platform,
			&e.Event.Metadata.ContainerName, &e.Event.Metadata.ContainerID,
			&e.Event.Metadata.State, &e.Event.Metadata.Status,
			&receivedStr, &acknowledgedAt, &tagID, &tagName)
		if err != nil {
			return nil, err
		}
		e.Event.Created, _ = time.Parse(time.RFC3339, createdStr)
		e.ReceivedAt, _ = time.Parse(time.RFC3339, receivedStr)
		e.Acknowledged = acknowledgedAt != ""
		if tagID.Valid && tagName.Valid {
			e.Tag = &Tag{ID: int(tagID.Int64), Name: tagName.String}
		}
		result[e.Event.Image] = e
	}
	return result, rows.Err()
}

func WebhookHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}

	var event DiunEvent

	if err := json.NewDecoder(r.Body).Decode(&event); err != nil {
		log.Printf("WebhookHandler: failed to decode request: %v", err)
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}

	if event.Image == "" {
		http.Error(w, "bad request: image field is required", http.StatusBadRequest)
		return
	}

	if err := UpdateEvent(event); err != nil {
		log.Printf("WebhookHandler: failed to store event: %v", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	log.Printf("Update received: %s (%s)", event.Image, event.Status)

	w.WriteHeader(http.StatusOK)
}

func UpdatesHandler(w http.ResponseWriter, r *http.Request) {
	updates, err := GetUpdates()
	if err != nil {
		log.Printf("UpdatesHandler: failed to get updates: %v", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	if err := json.NewEncoder(w).Encode(updates); err != nil {
		log.Printf("failed to encode updates: %v", err)
	}
}

func DismissHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPatch {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	image := strings.TrimPrefix(r.URL.Path, "/api/updates/")
	if image == "" {
		http.Error(w, "bad request: image name required", http.StatusBadRequest)
		return
	}
	mu.Lock()
	res, err := db.Exec(`UPDATE updates SET acknowledged_at = datetime('now') WHERE image = ?`, image)
	mu.Unlock()
	if err != nil {
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	n, _ := res.RowsAffected()
	if n == 0 {
		http.Error(w, "not found", http.StatusNotFound)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// TagsHandler handles GET /api/tags and POST /api/tags
func TagsHandler(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		rows, err := db.Query(`SELECT id, name FROM tags ORDER BY name`)
		if err != nil {
			http.Error(w, "internal error", http.StatusInternalServerError)
			return
		}
		defer rows.Close()
		tags := []Tag{}
		for rows.Next() {
			var t Tag
			if err := rows.Scan(&t.ID, &t.Name); err != nil {
				http.Error(w, "internal error", http.StatusInternalServerError)
				return
			}
			tags = append(tags, t)
		}
		if err := rows.Err(); err != nil {
			http.Error(w, "internal error", http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(tags)

	case http.MethodPost:
		var req struct {
			Name string `json:"name"`
		}
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.Name == "" {
			http.Error(w, "bad request: name required", http.StatusBadRequest)
			return
		}
		mu.Lock()
		res, err := db.Exec(`INSERT INTO tags (name) VALUES (?)`, req.Name)
		mu.Unlock()
		if err != nil {
			if strings.Contains(err.Error(), "UNIQUE") {
				http.Error(w, "conflict: tag name already exists", http.StatusConflict)
				return
			}
			http.Error(w, "internal error", http.StatusInternalServerError)
			return
		}
		id, _ := res.LastInsertId()
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusCreated)
		json.NewEncoder(w).Encode(Tag{ID: int(id), Name: req.Name})

	default:
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
	}
}

// TagByIDHandler handles DELETE /api/tags/{id}
func TagByIDHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodDelete {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	idStr := strings.TrimPrefix(r.URL.Path, "/api/tags/")
	id, err := strconv.Atoi(idStr)
	if err != nil || id <= 0 {
		http.Error(w, "bad request: invalid id", http.StatusBadRequest)
		return
	}
	mu.Lock()
	res, err := db.Exec(`DELETE FROM tags WHERE id = ?`, id)
	mu.Unlock()
	if err != nil {
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	n, _ := res.RowsAffected()
	if n == 0 {
		http.Error(w, "not found", http.StatusNotFound)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// TagAssignmentHandler handles PUT /api/tag-assignments and DELETE /api/tag-assignments
func TagAssignmentHandler(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodPut:
		var req struct {
			Image string `json:"image"`
			TagID int    `json:"tag_id"`
		}
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.Image == "" {
			http.Error(w, "bad request", http.StatusBadRequest)
			return
		}
		// Check tag exists
		var exists int
		err := db.QueryRow(`SELECT COUNT(*) FROM tags WHERE id = ?`, req.TagID).Scan(&exists)
		if err != nil || exists == 0 {
			http.Error(w, "not found: tag does not exist", http.StatusNotFound)
			return
		}
		mu.Lock()
		_, err = db.Exec(`INSERT OR REPLACE INTO tag_assignments (image, tag_id) VALUES (?, ?)`, req.Image, req.TagID)
		mu.Unlock()
		if err != nil {
			http.Error(w, "internal error", http.StatusInternalServerError)
			return
		}
		w.WriteHeader(http.StatusNoContent)

	case http.MethodDelete:
		var req struct {
			Image string `json:"image"`
		}
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.Image == "" {
			http.Error(w, "bad request", http.StatusBadRequest)
			return
		}
		mu.Lock()
		_, err := db.Exec(`DELETE FROM tag_assignments WHERE image = ?`, req.Image)
		mu.Unlock()
		if err != nil {
			http.Error(w, "internal error", http.StatusInternalServerError)
			return
		}
		w.WriteHeader(http.StatusNoContent)

	default:
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
	}
}