package tools

import (
	"context"
	"fmt"
	"io"
	"log/slog"
	"net"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/nextlevelbuilder/goclaw/internal/providers"
	"github.com/nextlevelbuilder/goclaw/internal/security"
	usagecaps "github.com/nextlevelbuilder/goclaw/internal/usage/caps"
)

// --- Context helpers for media video ---

const ctxMediaVideoRefs toolContextKey = "tool_media_video_refs"

// WithMediaVideoRefs stores video MediaRefs in context for read_video tool access.
func WithMediaVideoRefs(ctx context.Context, refs []providers.MediaRef) context.Context {
	return context.WithValue(ctx, ctxMediaVideoRefs, refs)
}

// MediaVideoRefsFromCtx retrieves stored video MediaRefs from context.
func MediaVideoRefsFromCtx(ctx context.Context) []providers.MediaRef {
	v, _ := ctx.Value(ctxMediaVideoRefs).([]providers.MediaRef)
	return v
}

// --- ReadVideoTool ---

// videoMaxBytes is the max file size for video analysis (100MB).
const videoMaxBytes = 100 * 1024 * 1024

const videoURLPinnedIPParam = "_pinned_ip"

// videoLocalPathParam forwards the resolved local file path so the budget probe can read the real file.
const videoLocalPathParam = "_local_path"

// videoProviderPriority is the order in which providers are tried for video analysis.
// OpenAI excluded — no native video upload in chat completions.
var videoProviderPriority = []string{"gemini", "openrouter"}

// videoModelDefaults maps provider names to preferred video-capable models.
var videoModelDefaults = map[string]string{
	"gemini":     "gemini-2.5-flash",
	"openrouter": "google/gemini-2.5-flash",
}

// ReadVideoTool uses a video-capable provider to analyze video files
// attached to the current conversation.
type ReadVideoTool struct {
	registry    *providers.Registry
	mediaLoader MediaPathLoader
	usageCaps   *usagecaps.Service
	// streamToGemini is injected per instance rather than through a package
	// global, so parallel tests cannot race each other over one seam.
	streamToGemini geminiStreamFn
}

// geminiStreamFn is the upload a gate-passing URL is handed to.
type geminiStreamFn func(ctx context.Context, apiKey, model, prompt string, reader io.Reader, contentLength int64, mime string, httpTimeout time.Duration) (*providers.ChatResponse, error)

func NewReadVideoTool(registry *providers.Registry, mediaLoader MediaPathLoader) *ReadVideoTool {
	return &ReadVideoTool{registry: registry, mediaLoader: mediaLoader, streamToGemini: geminiFileAPICallStream}
}

// setStreamToGeminiForTest observes what reaches the upload without contacting a provider.
func (t *ReadVideoTool) setStreamToGeminiForTest(fn geminiStreamFn) {
	t.streamToGemini = fn
}

func (t *ReadVideoTool) SetUsageCapService(svc *usagecaps.Service) {
	t.usageCaps = svc
}

func (t *ReadVideoTool) Name() string { return "read_video" }

func (t *ReadVideoTool) Description() string {
	return "Analyze video files attached to the conversation. " +
		"Use when you see <media:video> tags and need to describe, summarize, or analyze video content. " +
		"A workspace-relative path such as inputs/clip.mp4 may also be provided. Specify what you want to extract or analyze."
}

func (t *ReadVideoTool) Parameters() map[string]any {
	return map[string]any{
		"type": "object",
		"properties": map[string]any{
			"prompt": map[string]any{
				"type":        "string",
				"description": "What to analyze. E.g. 'Describe what happens in this video', 'Summarize the key scenes', 'What text appears on screen?'",
			},
			"media_id": map[string]any{
				"type":        "string",
				"description": "Optional: specific media_id from <media:video> tag. If omitted, uses most recent video.",
			},
			"url": map[string]any{
				"type":        "string",
				"description": "Optional URL to a video file. Use this to analyze videos hosted online.",
			},
			"path": map[string]any{
				"type":        "string",
				"description": "Optional workspace-relative video path. Delegated inputs use inputs/<name>.",
			},
		},
		"required": []string{"prompt"},
	}
}

func (t *ReadVideoTool) Execute(ctx context.Context, args map[string]any) *Result {
	prompt, _ := args["prompt"].(string)
	if prompt == "" {
		prompt = "Analyze this video and describe its contents."
	}
	mediaID, _ := args["media_id"].(string)
	videoURL, _ := args["url"].(string)
	videoArg, _ := args["path"].(string)

	sourceCount := 0
	for _, source := range []string{mediaID, videoURL, videoArg} {
		if source != "" {
			sourceCount++
		}
	}
	if sourceCount > 1 {
		if videoArg == "" && mediaID != "" && videoURL != "" {
			return ErrorResult("Both 'media_id' and 'url' parameters cannot be specified. Choose only one.")
		}
		return ErrorResult("Only one of 'media_id', 'url', or 'path' may be specified.")
	}

	var data []byte
	var videoMime string
	var videoPath string
	var pinnedIP net.IP

	if videoURL != "" {
		validatedURL, validatedIP, err := security.Validate(videoURL)
		if err != nil {
			return ErrorResult(fmt.Sprintf("Invalid video URL: %v", err))
		}
		pinnedIP = validatedIP

		// Infer MIME type from URL extension
		ext := filepath.Ext(validatedURL.Path)
		videoMime = mimeFromVideoExt(ext)
	} else {
		var mime string
		var err error
		if videoArg != "" {
			videoPath, err = resolveStructuredMediaPath(ctx, videoArg, "video")
			mime = mimeFromVideoExt(filepath.Ext(videoPath))
		} else {
			videoPath, mime, err = t.resolveVideoFile(ctx, mediaID)
		}
		if err != nil {
			return ErrorResult(err.Error())
		}
		videoMime = mime
		slog.Info("read_video: resolved file", "mime", videoMime, "media_id", mediaID, "logical_path", videoArg)

		fileData, err := os.ReadFile(videoPath)
		if err != nil {
			if videoArg != "" && IsDelegationArtifactRun(ctx) {
				return ErrorResult("Failed to read delegation video input")
			}
			return ErrorResult(fmt.Sprintf("Failed to read video file: %v", err))
		}
		slog.Info("read_video: file loaded", "size_bytes", len(fileData))
		if len(fileData) > videoMaxBytes {
			return ErrorResult(fmt.Sprintf("Video too large: %d bytes (max %d)", len(fileData), videoMaxBytes))
		}
		data = fileData
	}

	chain := ResolveMediaProviderChain(ctx, "read_video", "", "",
		videoProviderPriority, videoModelDefaults, t.registry)

	for i := range chain {
		if chain[i].Params == nil {
			chain[i].Params = make(map[string]any)
		}
		chain[i].Params["prompt"] = prompt
		chain[i].Params["data"] = data
		chain[i].Params["url"] = videoURL
		chain[i].Params["mime"] = videoMime
		chain[i].Params[videoLocalPathParam] = videoPath
		if pinnedIP != nil {
			chain[i].Params[videoURLPinnedIPParam] = pinnedIP
		}
	}

	chainResult, err := ExecuteWithChain(ctx, chain, t.registry, t.callProvider)
	if err != nil {
		return ErrorResult(fmt.Sprintf("Video analysis failed: %v", err))
	}

	result := NewResult(string(chainResult.Data))
	result.Usage = chainResult.Usage
	result.Provider = chainResult.Provider
	result.Model = chainResult.Model
	return result
}

// mimeFromVideoExt returns MIME type for video file extensions.
func mimeFromVideoExt(ext string) string {
	switch strings.ToLower(ext) {
	case ".mp4":
		return "video/mp4"
	case ".webm":
		return "video/webm"
	case ".mov":
		return "video/quicktime"
	case ".avi":
		return "video/x-msvideo"
	case ".mkv":
		return "video/x-matroska"
	case ".wmv":
		return "video/x-ms-wmv"
	case ".flv":
		return "video/x-flv"
	case ".3gp":
		return "video/3gpp"
	case ".mpeg", ".mpg":
		return "video/mpeg"
	default:
		return "video/mp4"
	}
}