package toolbox

import (
	"fmt"
	"os"
	"strings"

	toolutil "git.mlow.ca/mlow/lmcli/pkg/agent/toolbox/util"
	"git.mlow.ca/mlow/lmcli/pkg/api"
)

const FILE_REPLACE_LINES_DESCRIPTION = `Replace or remove a range of lines within a file, must specify path.

Useful for re-writing snippets/blocks of code or entire functions.

Plan your edits carefully and ensure any new content matches the flow and indentation of surrounding text.`

var FileReplaceLinesTool = api.ToolSpec{
	Name:        "file_replace_lines",
	Description: FILE_REPLACE_LINES_DESCRIPTION,
	Parameters: []api.ToolParameter{
		{
			Name:        "path",
			Type:        "string",
			Description: "Path of the file to be modified, relative to the current working directory.",
			Required:    true,
		},
		{
			Name:        "start_line",
			Type:        "integer",
			Description: `Line number which specifies the start of the replacement range (inclusive).`,
			Required:    true,
		},
		{
			Name:        "end_line",
			Type:        "integer",
			Description: `Line number which specifies the end of the replacement range (inclusive). If unset, range extends to end of file.`,
		},
		{
			Name:        "content",
			Type:        "string",
			Description: `Content to replace specified range. Omit to remove the specified range.`,
		},
	},
	Impl: func(tool *api.ToolSpec, args map[string]interface{}) (string, error) {
		tmp, ok := args["path"]
		if !ok {
			return "", fmt.Errorf("path parameter to write_file was not included.")
		}
		path, ok := tmp.(string)
		if !ok {
			return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
		}
		var start_line int
		tmp, ok = args["start_line"]
		if ok {
			tmp, ok := tmp.(float64)
			if !ok {
				return "", fmt.Errorf("Invalid start_line in function arguments: %v", tmp)
			}
			start_line = int(tmp)
		}
		var end_line int
		tmp, ok = args["end_line"]
		if ok {
			tmp, ok := tmp.(float64)
			if !ok {
				return "", fmt.Errorf("Invalid end_line in function arguments: %v", tmp)
			}
			end_line = int(tmp)
		}
		var content string
		tmp, ok = args["content"]
		if ok {
			content, ok = tmp.(string)
			if !ok {
				return "", fmt.Errorf("Invalid content in function arguments: %v", tmp)
			}
		}

		result := fileReplaceLines(path, start_line, end_line, content)
		ret, err := result.ToJson()
		if err != nil {
			return "", fmt.Errorf("Could not serialize result: %v", err)
		}
		return ret, nil
	},
}

func fileReplaceLines(path string, startLine int, endLine int, content string) api.CallResult {
	ok, reason := toolutil.IsPathWithinCWD(path)
	if !ok {
		return api.CallResult{Message: reason}
	}

	// Read the existing file's content
	data, err := os.ReadFile(path)
	if err != nil {
		if !os.IsNotExist(err) {
			return api.CallResult{Message: fmt.Sprintf("Could not read path: %s", err.Error())}
		}
		_, err = os.Create(path)
		if err != nil {
			return api.CallResult{Message: fmt.Sprintf("Could not create new file: %s", err.Error())}
		}
		data = []byte{}
	}

	if startLine < 1 {
		return api.CallResult{Message: "start_line cannot be less than 1"}
	}

	lines := strings.Split(string(data), "\n")
	contentLines := strings.Split(strings.Trim(content, "\n"), "\n")

	if endLine == 0 || endLine > len(lines) {
		endLine = len(lines)
	}

	before := lines[:startLine-1]
	after := lines[endLine:]

	lines = append(before, append(contentLines, after...)...)
	newContent := strings.Join(lines, "\n")

	// Join the lines and write back to the file
	err = os.WriteFile(path, []byte(newContent), 0644)
	if err != nil {
		return api.CallResult{Message: fmt.Sprintf("Could not write to path: %s", err.Error())}
	}

	return api.CallResult{Result: newContent}
}