package main

import (
	"context"
	"encoding/base64"
	"fmt"
	"net/http"
	"os"
	"strings"

	tea "github.com/charmbracelet/bubbletea"

	llm "gitea.stevedudenhoeffer.com/steve/go-llm/v2"
)

// Message types for async operations.

// ChatResponseMsg contains the response from a chat completion.
type ChatResponseMsg struct {
	Response llm.Response
	Err      error
}

// ToolExecutionMsg contains results from executing tool calls, one Message
// (RoleTool) per ToolCall, in the same order.
type ToolExecutionMsg struct {
	Results []llm.Message
	Err     error
}

// ImageLoadedMsg contains a loaded image.
type ImageLoadedMsg struct {
	Image llm.Image
	Err   error
}

// sendChatRequest sends a completion request with the current conversation,
// returning a ChatResponseMsg tea.Msg when the provider responds.
func sendChatRequest(model *llm.Model, messages []llm.Message, toolbox *llm.ToolBox, toolsEnabled bool, temperature *float64) tea.Cmd {
	return func() tea.Msg {
		opts := buildOpts(toolbox, toolsEnabled, temperature)
		resp, err := model.Complete(context.Background(), messages, opts...)
		return ChatResponseMsg{Response: resp, Err: err}
	}
}

// executeTools runs each tool call via the toolbox and returns ToolExecutionMsg
// with one RoleTool Message per call, in the same order.
func executeTools(toolbox *llm.ToolBox, calls []llm.ToolCall) tea.Cmd {
	return func() tea.Msg {
		ctx := context.Background()
		results, err := toolbox.ExecuteAll(ctx, calls)
		return ToolExecutionMsg{Results: results, Err: err}
	}
}

// buildOpts constructs RequestOptions from the current CLI state.
func buildOpts(toolbox *llm.ToolBox, toolsEnabled bool, temperature *float64) []llm.RequestOption {
	var opts []llm.RequestOption
	if toolsEnabled && toolbox != nil && len(toolbox.AllTools()) > 0 {
		opts = append(opts, llm.WithTools(toolbox))
	}
	if temperature != nil {
		opts = append(opts, llm.WithTemperature(*temperature))
	}
	return opts
}

// loadImageFromPath loads an image from a file path.
func loadImageFromPath(path string) tea.Cmd {
	return func() tea.Msg {
		path = strings.TrimSpace(path)
		path = strings.Trim(path, "\"'")

		data, err := os.ReadFile(path)
		if err != nil {
			return ImageLoadedMsg{Err: fmt.Errorf("failed to read image file: %w", err)}
		}

		contentType := http.DetectContentType(data)
		if !strings.HasPrefix(contentType, "image/") {
			return ImageLoadedMsg{Err: fmt.Errorf("file is not an image: %s", contentType)}
		}

		return ImageLoadedMsg{
			Image: llm.Image{
				Base64:      base64.StdEncoding.EncodeToString(data),
				ContentType: contentType,
			},
		}
	}
}

// loadImageFromURL loads an image from a URL (kept as URL, not fetched).
func loadImageFromURL(url string) tea.Cmd {
	return func() tea.Msg {
		return ImageLoadedMsg{Image: llm.Image{URL: strings.TrimSpace(url)}}
	}
}

// loadImageFromBase64 loads an image from base64 data (raw or data: URL).
func loadImageFromBase64(data string) tea.Cmd {
	return func() tea.Msg {
		data = strings.TrimSpace(data)

		if strings.HasPrefix(data, "data:") {
			parts := strings.SplitN(data, ",", 2)
			if len(parts) != 2 {
				return ImageLoadedMsg{Err: fmt.Errorf("invalid data URL format")}
			}
			mediaType := strings.TrimPrefix(parts[0], "data:")
			mediaType = strings.TrimSuffix(mediaType, ";base64")
			return ImageLoadedMsg{
				Image: llm.Image{
					Base64:      parts[1],
					ContentType: mediaType,
				},
			}
		}

		decoded, err := base64.StdEncoding.DecodeString(data)
		if err != nil {
			return ImageLoadedMsg{Err: fmt.Errorf("invalid base64 data: %w", err)}
		}
		contentType := http.DetectContentType(decoded)
		if !strings.HasPrefix(contentType, "image/") {
			return ImageLoadedMsg{Err: fmt.Errorf("data is not an image: %s", contentType)}
		}
		return ImageLoadedMsg{
			Image: llm.Image{
				Base64:      data,
				ContentType: contentType,
			},
		}
	}
}