package http

import (
	"context"
	"fmt"
	"time"

	"Moonshark/core/metadata"
	"Moonshark/core/routers"
	"Moonshark/core/runner"
	"Moonshark/core/runner/sandbox"
	"Moonshark/core/utils"
	"Moonshark/core/utils/config"
	"Moonshark/core/utils/logger"

	"github.com/goccy/go-json"
	"github.com/valyala/fasthttp"
)

// Server handles HTTP requests using Lua and static file routers
type Server struct {
	luaRouter      *routers.LuaRouter
	staticRouter   *routers.StaticRouter
	luaRunner      *runner.Runner
	fasthttpServer *fasthttp.Server
	loggingEnabled bool
	debugMode      bool
	config         *config.Config
	errorConfig    utils.ErrorPageConfig
}

// New creates a new HTTP server with optimized connection settings
func New(luaRouter *routers.LuaRouter, staticRouter *routers.StaticRouter, runner *runner.Runner,
	loggingEnabled bool, debugMode bool, overrideDir string, config *config.Config) *Server {

	server := &Server{
		luaRouter:      luaRouter,
		staticRouter:   staticRouter,
		luaRunner:      runner,
		loggingEnabled: loggingEnabled,
		debugMode:      debugMode,
		config:         config,
		errorConfig: utils.ErrorPageConfig{
			OverrideDir: overrideDir,
			DebugMode:   debugMode,
		},
	}

	// Configure fasthttp server
	server.fasthttpServer = &fasthttp.Server{
		Handler:                      server.handleRequest,
		Name:                         "Moonshark/" + metadata.Version,
		ReadTimeout:                  30 * time.Second,
		WriteTimeout:                 30 * time.Second,
		MaxRequestBodySize:           16 << 20, // 16MB - consistent with Forms.go
		DisableKeepalive:             false,
		TCPKeepalive:                 true,
		TCPKeepalivePeriod:           60 * time.Second,
		ReduceMemoryUsage:            true,
		GetOnly:                      false,
		DisablePreParseMultipartForm: true, // We'll handle parsing manually
	}

	return server
}

// ListenAndServe starts the server on the given address
func (s *Server) ListenAndServe(addr string) error {
	logger.ServerCont("Catch the swell at http://localhost%s", addr)
	return s.fasthttpServer.ListenAndServe(addr)
}

// Shutdown gracefully shuts down the server
func (s *Server) Shutdown(ctx context.Context) error {
	return s.fasthttpServer.ShutdownWithContext(ctx)
}

// handleRequest processes the HTTP request
func (s *Server) handleRequest(ctx *fasthttp.RequestCtx) {
	start := time.Now()
	method := string(ctx.Method())
	path := string(ctx.Path())

	// Special case for debug stats when debug mode is enabled
	if s.debugMode && path == "/debug/stats" {
		s.handleDebugStats(ctx)

		// Log request
		if s.loggingEnabled {
			duration := time.Since(start)
			LogRequest(ctx.Response.StatusCode(), method, path, duration)
		}
		return
	}

	// Process the request
	s.processRequest(ctx)

	// Log the request with our custom format
	if s.loggingEnabled {
		duration := time.Since(start)
		LogRequest(ctx.Response.StatusCode(), method, path, duration)
	}
}

// processRequest processes the actual request
func (s *Server) processRequest(ctx *fasthttp.RequestCtx) {
	method := string(ctx.Method())
	path := string(ctx.Path())

	logger.Debug("Processing request %s %s", method, path)

	// Try Lua routes first
	params := &routers.Params{}
	bytecode, scriptPath, found := s.luaRouter.GetBytecode(method, path, params)

	// Check if we found a route but it has no valid bytecode (compile error)
	if found && len(bytecode) == 0 {
		// Get the actual error from the router
		errorMsg := "Route exists but failed to compile. Check server logs for details."

		// Get the actual node to access its error
		if node, _ := s.luaRouter.GetNodeWithError(method, path, params); node != nil && node.Error != nil {
			errorMsg = node.Error.Error()
		}

		logger.Error("%s %s - %s", method, path, errorMsg)

		// Show error page with the actual error message
		ctx.SetContentType("text/html; charset=utf-8")
		ctx.SetStatusCode(fasthttp.StatusInternalServerError)
		errorHTML := utils.InternalErrorPage(s.errorConfig, path, errorMsg)
		ctx.SetBody([]byte(errorHTML))
		return
	} else if found {
		logger.Debug("Found Lua route match for %s %s with %d params", method, path, params.Count)
		s.handleLuaRoute(ctx, bytecode, scriptPath, params)
		return
	}

	// Then try static files
	if _, found := s.staticRouter.Match(path); found {
		s.staticRouter.ServeHTTP(ctx)
		return
	}

	// No route found - 404 Not Found
	ctx.SetContentType("text/html; charset=utf-8")
	ctx.SetStatusCode(fasthttp.StatusNotFound)
	ctx.SetBody([]byte(utils.NotFoundPage(s.errorConfig, path)))
}

// HandleMethodNotAllowed responds with a 405 Method Not Allowed error
func HandleMethodNotAllowed(ctx *fasthttp.RequestCtx, errorConfig utils.ErrorPageConfig) {
	path := string(ctx.Path())
	ctx.SetContentType("text/html; charset=utf-8")
	ctx.SetStatusCode(fasthttp.StatusMethodNotAllowed)
	ctx.SetBody([]byte(utils.MethodNotAllowedPage(errorConfig, path)))
}

// handleLuaRoute executes a Lua route
func (s *Server) handleLuaRoute(ctx *fasthttp.RequestCtx, bytecode []byte, scriptPath string, params *routers.Params) {
	luaCtx := runner.NewContext()
	defer luaCtx.Release()

	method := string(ctx.Method())
	path := string(ctx.Path())
	host := string(ctx.Host())

	// Set up context
	luaCtx.Set("method", method)
	luaCtx.Set("path", path)
	luaCtx.Set("host", host)

	// Headers
	headerMap := make(map[string]any)
	ctx.Request.Header.VisitAll(func(key, value []byte) {
		headerMap[string(key)] = string(value)
	})
	luaCtx.Set("headers", headerMap)

	// Cookies
	cookieMap := make(map[string]any)
	ctx.Request.Header.VisitAllCookie(func(key, value []byte) {
		cookieMap[string(key)] = string(value)
	})
	if len(cookieMap) > 0 {
		luaCtx.Set("cookies", cookieMap)
		luaCtx.Set("_request_cookies", cookieMap) // For backward compatibility
	} else {
		luaCtx.Set("cookies", make(map[string]any))
		luaCtx.Set("_request_cookies", make(map[string]any))
	}

	// URL parameters
	if params.Count > 0 {
		paramMap := make(map[string]any, params.Count)
		for i, key := range params.Keys {
			paramMap[key] = params.Values[i]
		}
		luaCtx.Set("params", paramMap)
	} else {
		luaCtx.Set("params", make(map[string]any))
	}

	// Query parameters
	queryMap := QueryToLua(ctx)
	luaCtx.Set("query", queryMap)

	// Form data
	if method == "POST" || method == "PUT" || method == "PATCH" {
		formData, err := ParseForm(ctx)
		if err == nil && len(formData) > 0 {
			luaCtx.Set("form", formData)
		} else if err != nil {
			logger.Warning("Error parsing form: %v", err)
			luaCtx.Set("form", make(map[string]any))
		} else {
			luaCtx.Set("form", make(map[string]any))
		}
	} else {
		luaCtx.Set("form", make(map[string]any))
	}

	// Execute Lua script
	result, err := s.luaRunner.Run(bytecode, luaCtx, scriptPath)

	// Special handling for CSRF error
	if err != nil {
		if csrfErr, ok := err.(*CSRFError); ok {
			logger.Warning("CSRF error executing Lua route: %v", csrfErr)
			HandleCSRFError(ctx, s.errorConfig)
			return
		}

		// Normal error handling
		logger.Error("Error executing Lua route: %v", err)
		ctx.SetContentType("text/html; charset=utf-8")
		ctx.SetStatusCode(fasthttp.StatusInternalServerError)
		errorHTML := utils.InternalErrorPage(s.errorConfig, path, err.Error())
		ctx.SetBody([]byte(errorHTML))
		return
	}

	writeResponse(ctx, result)
}

// Content types for responses
const (
	contentTypeJSON  = "application/json"
	contentTypePlain = "text/plain"
)

// writeResponse writes the Lua result to the HTTP response
func writeResponse(ctx *fasthttp.RequestCtx, result any) {
	if result == nil {
		ctx.SetStatusCode(fasthttp.StatusNoContent)
		return
	}

	// Check for HTTPResponse type
	if httpResp, ok := result.(*sandbox.HTTPResponse); ok {
		defer sandbox.ReleaseResponse(httpResp)

		// Set response headers
		for name, value := range httpResp.Headers {
			ctx.Response.Header.Set(name, value)
		}

		// Set cookies
		for _, cookie := range httpResp.Cookies {
			ctx.Response.Header.SetCookie(cookie)
		}

		// Set status code
		ctx.SetStatusCode(httpResp.Status)

		// Process the body based on its type
		if httpResp.Body == nil {
			return
		}

		result = httpResp.Body // Set result to body for processing below
	}

	// Check if it's a map (table) or array - return as JSON
	isJSON := false

	switch result.(type) {
	case map[string]any, []any, []float64, []string, []int:
		isJSON = true
	}

	if isJSON {
		setContentTypeIfMissing(ctx, contentTypeJSON)
		data, err := json.Marshal(result)
		if err != nil {
			logger.Error("Failed to marshal response: %v", err)
			ctx.Error("Internal Server Error", fasthttp.StatusInternalServerError)
			return
		}
		ctx.SetBody(data)
		return
	}

	// All other types - convert to plain text
	setContentTypeIfMissing(ctx, contentTypePlain)

	switch r := result.(type) {
	case string:
		ctx.SetBodyString(r)
	case []byte:
		ctx.SetBody(r)
	default:
		// Convert any other type to string
		ctx.SetBodyString(fmt.Sprintf("%v", r))
	}
}

func setContentTypeIfMissing(ctx *fasthttp.RequestCtx, contentType string) {
	if len(ctx.Response.Header.ContentType()) == 0 {
		ctx.SetContentType(contentType)
	}
}

// handleDebugStats displays debug statistics
func (s *Server) handleDebugStats(ctx *fasthttp.RequestCtx) {
	// Collect system stats
	stats := utils.CollectSystemStats(s.config)

	// Add component stats
	routeCount, bytecodeBytes := s.luaRouter.GetRouteStats()
	moduleCount := s.luaRunner.GetModuleCount()

	stats.Components = utils.ComponentStats{
		RouteCount:    routeCount,
		BytecodeBytes: bytecodeBytes,
		ModuleCount:   moduleCount,
	}

	// Generate HTML page
	html := utils.DebugStatsPage(stats)

	// Send the response
	ctx.SetContentType("text/html; charset=utf-8")
	ctx.SetStatusCode(fasthttp.StatusOK)
	ctx.SetBody([]byte(html))
}