package handlers

import (
	"database/sql"
	"encoding/json"

	"github.com/gin-gonic/gin"

	"git.gobha.me/xcaliber/chat-switchboard/models"
	"git.gobha.me/xcaliber/chat-switchboard/store"
)

// ExtensionHandler serves extension management endpoints.
type ExtensionHandler struct {
	stores store.Stores
}

func NewExtensionHandler(stores store.Stores) *ExtensionHandler {
	return &ExtensionHandler{stores: stores}
}

// ── User endpoints ──────────────────────────────

// ListUserExtensions returns all enabled extensions for the current user,
// with user-specific settings and enabled state merged in.
// GET /api/v1/extensions
func (h *ExtensionHandler) ListUserExtensions(c *gin.Context) {
	userID := c.GetString("user_id")
	tier := c.Query("tier") // optional filter

	exts, err := h.stores.Extensions.ListForUser(c.Request.Context(), userID)
	if err != nil {
		c.JSON(500, gin.H{"error": "failed to list extensions"})
		return
	}

	if tier != "" {
		filtered := make([]models.UserExtension, 0)
		for _, e := range exts {
			if e.Tier == tier {
				filtered = append(filtered, e)
			}
		}
		exts = filtered
	}

	c.JSON(200, gin.H{"data": exts})
}

// UpdateUserExtensionSettings saves per-user settings for an extension.
// POST /api/v1/extensions/:id/settings
func (h *ExtensionHandler) UpdateUserExtensionSettings(c *gin.Context) {
	userID := c.GetString("user_id")
	extID := c.Param("id")

	// Verify extension exists
	ext, err := h.stores.Extensions.GetByID(c.Request.Context(), extID)
	if err == sql.ErrNoRows {
		c.JSON(404, gin.H{"error": "extension not found"})
		return
	}
	if err != nil {
		c.JSON(500, gin.H{"error": "failed to fetch extension"})
		return
	}

	// System extensions can't be disabled by users
	var body struct {
		Settings  json.RawMessage `json:"settings"`
		IsEnabled *bool           `json:"is_enabled"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(400, gin.H{"error": "invalid request body"})
		return
	}

	enabled := true
	if body.IsEnabled != nil {
		if ext.IsSystem && !*body.IsEnabled {
			c.JSON(403, gin.H{"error": "system extensions cannot be disabled"})
			return
		}
		enabled = *body.IsEnabled
	}

	settings := json.RawMessage("{}")
	if body.Settings != nil {
		settings = body.Settings
	}

	eus := &models.ExtensionUserSettings{
		ExtensionID: extID,
		UserID:      userID,
		Settings:    settings,
		IsEnabled:   enabled,
	}
	if err := h.stores.Extensions.SetUserSettings(c.Request.Context(), eus); err != nil {
		c.JSON(500, gin.H{"error": "failed to save settings"})
		return
	}

	c.JSON(200, gin.H{"ok": true})
}

// ── Admin endpoints ─────────────────────────────

// AdminListExtensions returns all extensions (enabled and disabled).
// GET /api/v1/admin/extensions
func (h *ExtensionHandler) AdminListExtensions(c *gin.Context) {
	exts, err := h.stores.Extensions.ListAll(c.Request.Context())
	if err != nil {
		c.JSON(500, gin.H{"error": "failed to list extensions"})
		return
	}
	c.JSON(200, gin.H{"data": exts})
}

// AdminInstallExtension installs an extension from a manifest.
// POST /api/v1/admin/extensions
func (h *ExtensionHandler) AdminInstallExtension(c *gin.Context) {
	userID := c.GetString("user_id")

	var body struct {
		ExtID       string          `json:"ext_id" binding:"required"`
		Name        string          `json:"name" binding:"required"`
		Version     string          `json:"version"`
		Tier        string          `json:"tier"`
		Description string          `json:"description"`
		Author      string          `json:"author"`
		Manifest    json.RawMessage `json:"manifest"`
		IsSystem    bool            `json:"is_system"`
		IsEnabled   bool            `json:"is_enabled"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(400, gin.H{"error": "invalid request: " + err.Error()})
		return
	}

	// Defaults
	if body.Version == "" {
		body.Version = "0.0.0"
	}
	if body.Tier == "" {
		body.Tier = models.ExtTierBrowser
	}
	if body.Manifest == nil {
		body.Manifest = json.RawMessage("{}")
	}

	// Check for duplicate ext_id
	existing, err := h.stores.Extensions.GetByExtID(c.Request.Context(), body.ExtID)
	if err != nil && err != sql.ErrNoRows {
		c.JSON(500, gin.H{"error": "failed to check existing extension"})
		return
	}
	if existing != nil {
		c.JSON(409, gin.H{"error": "extension with ext_id '" + body.ExtID + "' already installed"})
		return
	}

	ext := &models.Extension{
		ExtID:       body.ExtID,
		Name:        body.Name,
		Version:     body.Version,
		Tier:        body.Tier,
		Description: body.Description,
		Author:      body.Author,
		Manifest:    body.Manifest,
		IsSystem:    body.IsSystem,
		IsEnabled:   body.IsEnabled,
		Scope:       models.ScopeGlobal,
		InstalledBy: &userID,
	}

	if err := h.stores.Extensions.Create(c.Request.Context(), ext); err != nil {
		c.JSON(500, gin.H{"error": "failed to install extension"})
		return
	}

	c.JSON(201, gin.H{"data": ext})
}

// AdminUpdateExtension updates an extension's config.
// PUT /api/v1/admin/extensions/:id
func (h *ExtensionHandler) AdminUpdateExtension(c *gin.Context) {
	id := c.Param("id")

	ext, err := h.stores.Extensions.GetByID(c.Request.Context(), id)
	if err == sql.ErrNoRows {
		c.JSON(404, gin.H{"error": "extension not found"})
		return
	}
	if err != nil {
		c.JSON(500, gin.H{"error": "failed to fetch extension"})
		return
	}

	var body struct {
		Name        *string          `json:"name"`
		Description *string          `json:"description"`
		IsSystem    *bool            `json:"is_system"`
		IsEnabled   *bool            `json:"is_enabled"`
		Manifest    *json.RawMessage `json:"manifest"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(400, gin.H{"error": "invalid request body"})
		return
	}

	if body.Name != nil {
		ext.Name = *body.Name
	}
	if body.Description != nil {
		ext.Description = *body.Description
	}
	if body.IsSystem != nil {
		ext.IsSystem = *body.IsSystem
	}
	if body.IsEnabled != nil {
		ext.IsEnabled = *body.IsEnabled
	}
	if body.Manifest != nil {
		ext.Manifest = *body.Manifest
	}

	if err := h.stores.Extensions.Update(c.Request.Context(), id, ext); err != nil {
		c.JSON(500, gin.H{"error": "failed to update extension"})
		return
	}

	c.JSON(200, gin.H{"data": ext})
}

// ServeExtensionAsset serves browser extension JS files.
// GET /api/v1/extensions/:id/assets/*path
//
// For the MVP, scripts are stored inline in manifest._script.
// The :id param is the ext_id (e.g. "mermaid-renderer"), not the UUID.
func (h *ExtensionHandler) ServeExtensionAsset(c *gin.Context) {
	extID := c.Param("id")
	// path := c.Param("path") // reserved for future multi-file support

	ext, err := h.stores.Extensions.GetByExtID(c.Request.Context(), extID)
	if err != nil {
		c.JSON(404, gin.H{"error": "extension not found"})
		return
	}

	if !ext.IsEnabled {
		c.JSON(404, gin.H{"error": "extension not enabled"})
		return
	}

	// Extract inline script from manifest
	var manifest map[string]json.RawMessage
	if err := json.Unmarshal(ext.Manifest, &manifest); err != nil {
		c.JSON(500, gin.H{"error": "invalid manifest"})
		return
	}

	scriptRaw, ok := manifest["_script"]
	if !ok {
		c.JSON(404, gin.H{"error": "no script in manifest"})
		return
	}

	// _script is a JSON string — unquote it
	var script string
	if err := json.Unmarshal(scriptRaw, &script); err != nil {
		c.JSON(500, gin.H{"error": "invalid script in manifest"})
		return
	}

	c.Header("Content-Type", "application/javascript; charset=utf-8")
	c.Header("Cache-Control", "public, max-age=3600")
	c.String(200, script)
}

// GetExtensionManifest returns the manifest for a specific extension.
// GET /api/v1/extensions/:id/manifest
func (h *ExtensionHandler) GetExtensionManifest(c *gin.Context) {
	extID := c.Param("id")

	ext, err := h.stores.Extensions.GetByExtID(c.Request.Context(), extID)
	if err != nil {
		c.JSON(404, gin.H{"error": "extension not found"})
		return
	}

	c.JSON(200, gin.H{"data": ext.Manifest})
}

// ListBrowserToolSchemas returns tool schemas from all enabled browser extensions.
// Used by the completion handler to include browser tools in LLM requests.
// GET /api/v1/extensions/tools
func (h *ExtensionHandler) ListBrowserToolSchemas(c *gin.Context) {
	userID := c.GetString("user_id")

	exts, err := h.stores.Extensions.ListForUser(c.Request.Context(), userID)
	if err != nil {
		c.JSON(500, gin.H{"error": "failed to list extensions"})
		return
	}

	var toolSchemas []json.RawMessage
	for _, ext := range exts {
		if ext.Tier != "browser" {
			continue
		}
		var manifest struct {
			Tools []json.RawMessage `json:"tools"`
		}
		if err := json.Unmarshal(ext.Manifest, &manifest); err != nil {
			continue
		}
		toolSchemas = append(toolSchemas, manifest.Tools...)
	}

	if toolSchemas == nil {
		toolSchemas = make([]json.RawMessage, 0)
	}
	c.JSON(200, gin.H{"data": toolSchemas})
}

// AdminUninstallExtension removes an extension.
// DELETE /api/v1/admin/extensions/:id
func (h *ExtensionHandler) AdminUninstallExtension(c *gin.Context) {
	id := c.Param("id")

	_, err := h.stores.Extensions.GetByID(c.Request.Context(), id)
	if err == sql.ErrNoRows {
		c.JSON(404, gin.H{"error": "extension not found"})
		return
	}
	if err != nil {
		c.JSON(500, gin.H{"error": "failed to fetch extension"})
		return
	}

	if err := h.stores.Extensions.Delete(c.Request.Context(), id); err != nil {
		c.JSON(500, gin.H{"error": "failed to uninstall extension"})
		return
	}

	c.JSON(200, gin.H{"ok": true})
}