package cmd

import (
	"cmp"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"slices"
	"strings"

	"github.com/spf13/cobra"

	"github.com/ollama/ollama/api"
	"github.com/ollama/ollama/envconfig"
	"github.com/ollama/ollama/internal/modelref"
	"github.com/ollama/ollama/readline"
	"github.com/ollama/ollama/types/errtypes"
	"github.com/ollama/ollama/types/model"
)

type MultilineState int

const (
	MultilineNone MultilineState = iota
	MultilinePrompt
	MultilineSystem
)

func generateInteractive(cmd *cobra.Command, opts runOptions) error {
	usage := func() {
		fmt.Fprintln(os.Stderr, "Available Commands:")
		fmt.Fprintln(os.Stderr, "  /set            Set session variables")
		fmt.Fprintln(os.Stderr, "  /show           Show model information")
		fmt.Fprintln(os.Stderr, "  /load <model>   Load a session or model")
		fmt.Fprintln(os.Stderr, "  /save <model>   Save your current session")
		fmt.Fprintln(os.Stderr, "  /clear          Clear session context")
		fmt.Fprintln(os.Stderr, "  /bye            Exit")
		fmt.Fprintln(os.Stderr, "  /?, /help       Help for a command")
		fmt.Fprintln(os.Stderr, "  /? shortcuts    Help for keyboard shortcuts")

		fmt.Fprintln(os.Stderr, "")
		fmt.Fprintln(os.Stderr, "Use \"\"\" to begin a multi-line message.")

		if opts.MultiModal {
			fmt.Fprintf(os.Stderr, "Use %s to include .jpg, .png, .webp images, or .wav audio files.\n", filepath.FromSlash("/path/to/file"))
		}

		fmt.Fprintln(os.Stderr, "")
	}

	usageSet := func() {
		fmt.Fprintln(os.Stderr, "Available Commands:")
		fmt.Fprintln(os.Stderr, "  /set parameter ...     Set a parameter")
		fmt.Fprintln(os.Stderr, "  /set system <string>   Set system message")
		fmt.Fprintln(os.Stderr, "  /set history           Enable history")
		fmt.Fprintln(os.Stderr, "  /set nohistory         Disable history")
		fmt.Fprintln(os.Stderr, "  /set wordwrap          Enable wordwrap")
		fmt.Fprintln(os.Stderr, "  /set nowordwrap        Disable wordwrap")
		fmt.Fprintln(os.Stderr, "  /set format json       Enable JSON mode")
		fmt.Fprintln(os.Stderr, "  /set noformat          Disable formatting")
		fmt.Fprintln(os.Stderr, "  /set verbose           Show LLM stats")
		fmt.Fprintln(os.Stderr, "  /set quiet             Disable LLM stats")
		fmt.Fprintln(os.Stderr, "  /set think             Enable thinking")
		fmt.Fprintln(os.Stderr, "  /set nothink           Disable thinking")
		fmt.Fprintln(os.Stderr, "")
	}

	usageShortcuts := func() {
		fmt.Fprintln(os.Stderr, "Available keyboard shortcuts:")
		fmt.Fprintln(os.Stderr, "  Ctrl + a            Move to the beginning of the line (Home)")
		fmt.Fprintln(os.Stderr, "  Ctrl + e            Move to the end of the line (End)")
		fmt.Fprintln(os.Stderr, "   Alt + b            Move back (left) one word")
		fmt.Fprintln(os.Stderr, "   Alt + f            Move forward (right) one word")
		fmt.Fprintln(os.Stderr, "  Ctrl + k            Delete the sentence after the cursor")
		fmt.Fprintln(os.Stderr, "  Ctrl + u            Delete the sentence before the cursor")
		fmt.Fprintln(os.Stderr, "  Ctrl + w            Delete the word before the cursor")
		fmt.Fprintln(os.Stderr, "")
		fmt.Fprintln(os.Stderr, "  Ctrl + l            Clear the screen")
		fmt.Fprintln(os.Stderr, "  Ctrl + g            Open default editor to compose a prompt")
		fmt.Fprintln(os.Stderr, "  Ctrl + c            Stop the model from responding")
		fmt.Fprintln(os.Stderr, "  Ctrl + d            Exit ollama (/bye)")
		fmt.Fprintln(os.Stderr, "")
	}

	usageShow := func() {
		fmt.Fprintln(os.Stderr, "Available Commands:")
		fmt.Fprintln(os.Stderr, "  /show info         Show details for this model")
		fmt.Fprintln(os.Stderr, "  /show license      Show model license")
		fmt.Fprintln(os.Stderr, "  /show modelfile    Show Modelfile for this model")
		fmt.Fprintln(os.Stderr, "  /show parameters   Show parameters for this model")
		fmt.Fprintln(os.Stderr, "  /show system       Show system message")
		fmt.Fprintln(os.Stderr, "  /show template     Show prompt template")
		fmt.Fprintln(os.Stderr, "")
	}

	// only list out the most common parameters
	usageParameters := func() {
		fmt.Fprintln(os.Stderr, "Available Parameters:")
		fmt.Fprintln(os.Stderr, "  /set parameter seed <int>             Random number seed")
		fmt.Fprintln(os.Stderr, "  /set parameter num_predict <int>      Max number of tokens to predict")
		fmt.Fprintln(os.Stderr, "  /set parameter top_k <int>            Pick from top k num of tokens")
		fmt.Fprintln(os.Stderr, "  /set parameter top_p <float>          Pick token based on sum of probabilities")
		fmt.Fprintln(os.Stderr, "  /set parameter min_p <float>          Pick token based on top token probability * min_p")
		fmt.Fprintln(os.Stderr, "  /set parameter num_ctx <int>          Set the context size")
		fmt.Fprintln(os.Stderr, "  /set parameter temperature <float>    Set creativity level")
		fmt.Fprintln(os.Stderr, "  /set parameter repeat_penalty <float> How strongly to penalize repetitions")
		fmt.Fprintln(os.Stderr, "  /set parameter repeat_last_n <int>    Set how far back to look for repetitions")
		fmt.Fprintln(os.Stderr, "  /set parameter num_gpu <int>          The number of layers to send to the GPU")
		fmt.Fprintln(os.Stderr, "  /set parameter stop <string> <string> ...   Set the stop parameters")
		fmt.Fprintln(os.Stderr, "")
	}

	scanner, err := readline.New(readline.Prompt{
		Prompt:         ">>> ",
		AltPrompt:      "... ",
		Placeholder:    "Send a message (/? for help)",
		AltPlaceholder: "Press Enter to send",
	})
	if err != nil {
		return err
	}

	if envconfig.NoHistory() {
		scanner.HistoryDisable()
	}

	fmt.Print(readline.StartBracketedPaste)
	defer fmt.Printf(readline.EndBracketedPaste)

	var sb strings.Builder
	var multiline MultilineState
	var thinkExplicitlySet bool = opts.Think != nil

	for {
		line, err := scanner.Readline()
		switch {
		case errors.Is(err, io.EOF):
			fmt.Println()
			return nil
		case errors.Is(err, readline.ErrInterrupt):
			if line == "" {
				fmt.Println("\nUse Ctrl + d or /bye to exit.")
			}

			scanner.Prompt.UseAlt = false
			sb.Reset()

			continue
		case errors.Is(err, readline.ErrEditPrompt):
			sb.Reset()
			content, err := editInExternalEditor(line)
			if err != nil {
				fmt.Fprintf(os.Stderr, "error: %v\n", err)
				continue
			}
			if strings.TrimSpace(content) == "" {
				continue
			}
			scanner.Prefill = content
			continue
		case err != nil:
			return err
		}

		switch {
		case multiline != MultilineNone:
			// check if there's a multiline terminating string
			before, ok := strings.CutSuffix(line, `"""`)
			sb.WriteString(before)
			if !ok {
				fmt.Fprintln(&sb)
				scanner.Prompt.UseAlt = true
				continue
			}

			switch multiline {
			case MultilineSystem:
				opts.System = sb.String()
				opts.Messages = append(opts.Messages, api.Message{Role: "system", Content: opts.System})
				fmt.Println("Set system message.")
				sb.Reset()
			}

			multiline = MultilineNone
			scanner.Prompt.UseAlt = false
		case strings.HasPrefix(line, `"""`):
			line := strings.TrimPrefix(line, `"""`)
			line, ok := strings.CutSuffix(line, `"""`)
			sb.WriteString(line)
			if !ok {
				// no multiline terminating string; need more input
				fmt.Fprintln(&sb)
				multiline = MultilinePrompt
				scanner.Prompt.UseAlt = true
			}
		case scanner.Pasting:
			fmt.Fprintln(&sb, line)
			continue
		case strings.HasPrefix(line, "/list"):
			args := strings.Fields(line)
			if err := ListHandler(cmd, args[1:]); err != nil {
				return err
			}
		case strings.HasPrefix(line, "/load"):
			args := strings.Fields(line)
			if len(args) != 2 {
				fmt.Println("Usage:\n  /load <modelname>")
				continue
			}
			origOpts := opts.Copy()

			client, err := api.ClientFromEnvironment()
			if err != nil {
				fmt.Println("error: couldn't connect to ollama server")
				return err
			}

			opts.Model = args[1]
			opts.Messages = []api.Message{}
			opts.LoadedMessages = nil
			fmt.Printf("Loading model '%s'\n", opts.Model)
			info, err := client.Show(cmd.Context(), &api.ShowRequest{Model: opts.Model})
			if err != nil {
				if strings.Contains(err.Error(), "not found") {
					fmt.Printf("Couldn't find model '%s'\n", opts.Model)
					opts = origOpts.Copy()
					continue
				}
				return err
			}
			applyShowResponseToRunOptions(&opts, info)
			opts.Think, err = inferThinkingOption(&info.Capabilities, &opts, thinkExplicitlySet)
			if err != nil {
				return err
			}
			if err := loadOrUnloadModel(cmd, &opts); err != nil {
				if strings.Contains(err.Error(), "not found") {
					fmt.Printf("Couldn't find model '%s'\n", opts.Model)
					opts = origOpts.Copy()
					continue
				}
				if strings.Contains(err.Error(), "does not support thinking") {
					fmt.Printf("error: %v\n", err)
					continue
				}
				return err
			}
			continue
		case strings.HasPrefix(line, "/save"):
			args := strings.Fields(line)
			if len(args) != 2 {
				fmt.Println("Usage:\n  /save <modelname>")
				continue
			}

			client, err := api.ClientFromEnvironment()
			if err != nil {
				fmt.Println("error: couldn't connect to ollama server")
				return err
			}

			req := NewCreateRequest(args[1], opts)
			fn := func(resp api.ProgressResponse) error { return nil }
			err = client.Create(cmd.Context(), req, fn)
			if err != nil {
				if strings.Contains(err.Error(), errtypes.InvalidModelNameErrMsg) {
					fmt.Printf("error: The model name '%s' is invalid\n", args[1])
					continue
				}
				return err
			}
			fmt.Printf("Created new model '%s'\n", args[1])
			continue
		case strings.HasPrefix(line, "/clear"):
			opts.Messages = []api.Message{}
			if opts.System != "" {
				newMessage := api.Message{Role: "system", Content: opts.System}
				opts.Messages = append(opts.Messages, newMessage)
			}
			fmt.Println("Cleared session context")
			continue
		case strings.HasPrefix(line, "/set"):
			args := strings.Fields(line)
			if len(args) > 1 {
				switch args[1] {
				case "history":
					scanner.HistoryEnable()
				case "nohistory":
					scanner.HistoryDisable()
				case "wordwrap":
					opts.WordWrap = true
					fmt.Println("Set 'wordwrap' mode.")
				case "nowordwrap":
					opts.WordWrap = false
					fmt.Println("Set 'nowordwrap' mode.")
				case "verbose":
					if err := cmd.Flags().Set("verbose", "true"); err != nil {
						return err
					}
					fmt.Println("Set 'verbose' mode.")
				case "quiet":
					if err := cmd.Flags().Set("verbose", "false"); err != nil {
						return err
					}
					fmt.Println("Set 'quiet' mode.")
				case "think":
					thinkValue := api.ThinkValue{Value: true}
					var maybeLevel string
					if len(args) > 2 {
						maybeLevel = args[2]
					}
					if maybeLevel != "" {
						// TODO(drifkin): validate the level, could be model dependent
						// though... It will also be validated on the server once a call is
						// made.
						thinkValue.Value = maybeLevel
					}
					opts.Think = &thinkValue
					thinkExplicitlySet = true
					if client, err := api.ClientFromEnvironment(); err == nil {
						ensureThinkingSupport(cmd.Context(), client, opts.Model)
					}
					if maybeLevel != "" {
						fmt.Printf("Set 'think' mode to '%s'.\n", maybeLevel)
					} else {
						fmt.Println("Set 'think' mode.")
					}
				case "nothink":
					opts.Think = &api.ThinkValue{Value: false}
					thinkExplicitlySet = true
					if client, err := api.ClientFromEnvironment(); err == nil {
						ensureThinkingSupport(cmd.Context(), client, opts.Model)
					}
					fmt.Println("Set 'nothink' mode.")
				case "format":
					if len(args) < 3 || args[2] != "json" {
						fmt.Println("Invalid or missing format. For 'json' mode use '/set format json'")
					} else {
						opts.Format = args[2]
						fmt.Printf("Set format to '%s' mode.\n", args[2])
					}
				case "noformat":
					opts.Format = ""
					fmt.Println("Disabled format.")
				case "parameter":
					if len(args) < 4 {
						usageParameters()
						continue
					}
					params := args[3:]
					fp, err := api.FormatParams(map[string][]string{args[2]: params})
					if err != nil {
						fmt.Printf("Couldn't set parameter: %q\n", err)
						continue
					}
					fmt.Printf("Set parameter '%s' to '%s'\n", args[2], strings.Join(params, ", "))
					opts.Options[args[2]] = fp[args[2]]
				case "system":
					if len(args) < 3 {
						usageSet()
						continue
					}

					multiline = MultilineSystem

					line := strings.Join(args[2:], " ")
					line, ok := strings.CutPrefix(line, `"""`)
					if !ok {
						multiline = MultilineNone
					} else {
						// only cut suffix if the line is multiline
						line, ok = strings.CutSuffix(line, `"""`)
						if ok {
							multiline = MultilineNone
						}
					}

					sb.WriteString(line)
					if multiline != MultilineNone {
						scanner.Prompt.UseAlt = true
						continue
					}

					opts.System = sb.String() // for display in modelfile
					newMessage := api.Message{Role: "system", Content: sb.String()}
					// Check if the slice is not empty and the last message is from 'system'
					if len(opts.Messages) > 0 && opts.Messages[len(opts.Messages)-1].Role == "system" {
						// Replace the last message
						opts.Messages[len(opts.Messages)-1] = newMessage
					} else {
						opts.Messages = append(opts.Messages, newMessage)
					}
					fmt.Println("Set system message.")
					sb.Reset()
					continue
				default:
					fmt.Printf("Unknown command '/set %s'. Type /? for help\n", args[1])
				}
			} else {
				usageSet()
			}
		case strings.HasPrefix(line, "/show"):
			args := strings.Fields(line)
			if len(args) > 1 {
				client, err := api.ClientFromEnvironment()
				if err != nil {
					fmt.Println("error: couldn't connect to ollama server")
					return err
				}
				req := &api.ShowRequest{
					Name:    opts.Model,
					System:  opts.System,
					Options: opts.Options,
				}
				resp, err := client.Show(cmd.Context(), req)
				if err != nil {
					fmt.Println("error: couldn't get model")
					return err
				}

				switch args[1] {
				case "info":
					_ = showInfo(resp, false, os.Stderr)
				case "license":
					if resp.License == "" {
						fmt.Println("No license was specified for this model.")
					} else {
						fmt.Println(resp.License)
					}
				case "modelfile":
					fmt.Println(resp.Modelfile)
				case "parameters":
					fmt.Println("Model defined parameters:")
					if resp.Parameters == "" {
						fmt.Println("  No additional parameters were specified for this model.")
					} else {
						for _, l := range strings.Split(resp.Parameters, "\n") {
							fmt.Printf("  %s\n", l)
						}
					}
					fmt.Println()
					if len(opts.Options) > 0 {
						fmt.Println("User defined parameters:")
						for k, v := range opts.Options {
							fmt.Printf("  %-*s %v\n", 30, k, v)
						}
						fmt.Println()
					}
				case "system":
					switch {
					case opts.System != "":
						fmt.Println(opts.System + "\n")
					case resp.System != "":
						fmt.Println(resp.System + "\n")
					default:
						fmt.Println("No system message was specified for this model.")
					}
				case "template":
					if resp.Template != "" {
						fmt.Println(resp.Template)
					} else {
						fmt.Println("No prompt template was specified for this model.")
					}
				default:
					fmt.Printf("Unknown command '/show %s'. Type /? for help\n", args[1])
				}
			} else {
				usageShow()
			}
		case strings.HasPrefix(line, "/help"), strings.HasPrefix(line, "/?"):
			args := strings.Fields(line)
			if len(args) > 1 {
				switch args[1] {
				case "set", "/set":
					usageSet()
				case "show", "/show":
					usageShow()
				case "shortcut", "shortcuts":
					usageShortcuts()
				}
			} else {
				usage()
			}
		case strings.HasPrefix(line, "/exit"), strings.HasPrefix(line, "/bye"):
			return nil
		case strings.HasPrefix(line, "/"):
			args := strings.Fields(line)
			isFile := false

			if opts.MultiModal {
				for _, f := range extractFileNames(line) {
					if strings.HasPrefix(f, args[0]) {
						isFile = true
						break
					}
				}
			}

			if !isFile {
				fmt.Printf("Unknown command '%s'. Type /? for help\n", args[0])
				continue
			}

			sb.WriteString(line)
		default:
			sb.WriteString(line)
		}

		if sb.Len() > 0 && multiline == MultilineNone {
			newMessage := api.Message{Role: "user", Content: sb.String()}

			if opts.MultiModal {
				msg, images, err := extractFileData(sb.String())
				if err != nil {
					return err
				}

				newMessage.Content = msg
				newMessage.Images = images
			}

			opts.Messages = append(opts.Messages, newMessage)

			assistant, err := chat(cmd, opts)
			if err != nil {
				if strings.Contains(err.Error(), "does not support thinking") ||
					strings.Contains(err.Error(), "invalid think value") {
					fmt.Printf("error: %v\n", err)
					sb.Reset()
					continue
				}
				return err
			}
			if assistant != nil {
				opts.Messages = append(opts.Messages, *assistant)
			}

			sb.Reset()
		}
	}
}

func NewCreateRequest(name string, opts runOptions) *api.CreateRequest {
	parentModel := opts.ParentModel

	modelName := model.ParseName(parentModel)
	if !modelName.IsValid() {
		parentModel = ""
	}

	// Preserve explicit cloud intent for sessions started with `:cloud`.
	// Cloud model metadata can return a source-less parent_model (for example
	// "qwen3.5"), which would otherwise make `/save` create a local derivative.
	if modelref.HasExplicitCloudSource(opts.Model) && !modelref.HasExplicitCloudSource(parentModel) {
		parentModel = ""
	}

	req := &api.CreateRequest{
		Model: name,
		From:  cmp.Or(parentModel, opts.Model),
	}

	if opts.System != "" {
		req.System = opts.System
	}

	if len(opts.Options) > 0 {
		req.Parameters = opts.Options
	}

	messages := slices.Clone(opts.LoadedMessages)
	messages = append(messages, opts.Messages...)
	if len(messages) > 0 {
		req.Messages = messages
	}

	return req
}

func normalizeFilePath(fp string) string {
	return strings.NewReplacer(
		"\\ ", " ", // Escaped space
		"\\(", "(", // Escaped left parenthesis
		"\\)", ")", // Escaped right parenthesis
		"\\[", "[", // Escaped left square bracket
		"\\]", "]", // Escaped right square bracket
		"\\{", "{", // Escaped left curly brace
		"\\}", "}", // Escaped right curly brace
		"\\$", "$", // Escaped dollar sign
		"\\&", "&", // Escaped ampersand
		"\\;", ";", // Escaped semicolon
		"\\'", "'", // Escaped single quote
		"\\\\", "\\", // Escaped backslash
		"\\*", "*", // Escaped asterisk
		"\\?", "?", // Escaped question mark
		"\\~", "~", // Escaped tilde
	).Replace(fp)
}

func extractFileNames(input string) []string {
	// Regex to match file paths starting with optional drive letter, / ./ \ or .\ and include escaped or unescaped spaces (\ or %20)
	// and followed by more characters and a file extension
	// This will capture non filename strings, but we'll check for file existence to remove mismatches
	regexPattern := `(?:[a-zA-Z]:)?(?:\./|/|\\)[\S\\ ]+?\.(?i:jpg|jpeg|png|webp|wav)\b`
	re := regexp.MustCompile(regexPattern)

	return re.FindAllString(input, -1)
}

func extractFileData(input string) (string, []api.ImageData, error) {
	filePaths := extractFileNames(input)
	var imgs []api.ImageData

	for _, fp := range filePaths {
		nfp := normalizeFilePath(fp)
		data, err := getImageData(nfp)
		if errors.Is(err, os.ErrNotExist) {
			continue
		} else if err != nil {
			fmt.Fprintf(os.Stderr, "Couldn't process file: %q\n", err)
			return "", imgs, err
		}
		ext := strings.ToLower(filepath.Ext(nfp))
		switch ext {
		case ".wav":
			fmt.Fprintf(os.Stderr, "Added audio '%s'\n", nfp)
		default:
			fmt.Fprintf(os.Stderr, "Added image '%s'\n", nfp)
		}
		input = strings.ReplaceAll(input, "'"+nfp+"'", "")
		input = strings.ReplaceAll(input, "'"+fp+"'", "")
		input = strings.ReplaceAll(input, fp, "")
		imgs = append(imgs, data)
	}
	return strings.TrimSpace(input), imgs, nil
}

func editInExternalEditor(content string) (string, error) {
	editor := envconfig.Editor()
	if editor == "" {
		editor = os.Getenv("VISUAL")
	}
	if editor == "" {
		editor = os.Getenv("EDITOR")
	}
	if editor == "" {
		editor = defaultEditor
	}

	// Check that the editor binary exists
	name := strings.Fields(editor)[0]
	if _, err := exec.LookPath(name); err != nil {
		return "", fmt.Errorf("editor %q not found, set OLLAMA_EDITOR to the path of your preferred editor", name)
	}

	tmpFile, err := os.CreateTemp("", "ollama-prompt-*.txt")
	if err != nil {
		return "", fmt.Errorf("creating temp file: %w", err)
	}
	defer os.Remove(tmpFile.Name())

	if content != "" {
		if _, err := tmpFile.WriteString(content); err != nil {
			tmpFile.Close()
			return "", fmt.Errorf("writing to temp file: %w", err)
		}
	}
	tmpFile.Close()

	args := strings.Fields(editor)
	args = append(args, tmpFile.Name())
	cmd := exec.Command(args[0], args[1:]...)
	cmd.Stdin = os.Stdin
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	if err := cmd.Run(); err != nil {
		return "", fmt.Errorf("editor exited with error: %w", err)
	}

	data, err := os.ReadFile(tmpFile.Name())
	if err != nil {
		return "", fmt.Errorf("reading temp file: %w", err)
	}

	return strings.TrimRight(string(data), "\n"), nil
}

func getImageData(filePath string) ([]byte, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	buf := make([]byte, 512)
	_, err = file.Read(buf)
	if err != nil {
		return nil, err
	}

	contentType := http.DetectContentType(buf)
	allowedTypes := []string{"image/jpeg", "image/jpg", "image/png", "image/webp", "audio/wave"}
	if !slices.Contains(allowedTypes, contentType) {
		return nil, fmt.Errorf("invalid file type: %s", contentType)
	}

	info, err := file.Stat()
	if err != nil {
		return nil, err
	}

	var maxSize int64 = 100 * 1024 * 1024 // 100MB
	if info.Size() > maxSize {
		return nil, errors.New("file size exceeds maximum limit (100MB)")
	}

	buf = make([]byte, info.Size())
	_, err = file.Seek(0, 0)
	if err != nil {
		return nil, err
	}

	_, err = io.ReadFull(file, buf)
	if err != nil {
		return nil, err
	}

	return buf, nil
}
