package toolbox

import (
	"fmt"
	"os"
	"strings"

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

var MODIFY_FILE_DESCRIPTION = []string{
    "Modify a file. If the file does not exist, it will be created.",
    "",
    "Content can be either inserted, replaced, or removed through a combination of the start, stop, and content parameters.",
    "Use the start and stop line numbers to limit the range of modification to the file.",
    "If both `start` and `stop` are left unset (or set to 0), the entire file's contents will be updated.",
    "If `start` is set to n and `stop` to n+1, content will be inserted at line n (the content that was at line n will be shifted below the newly inserted content).",
    "If only `start` is set, content from the given line and onwards will be updated.",
    "If only `stop` is set, content up to but not including the given line will be updated.",
    "",
    "Examples:",
    "1. Append to a file:",
    "   {\"path\": \"example.txt\", \"start\": <last_line_number + 1>, \"content\": \"New content to append\"}",
    "",
    "2. Insert at a specific line:",
    "   {\"path\": \"example.txt\", \"start\": 5, \"stop\": 5, \"content\": \"New line inserted above the previous line 5\"}",
    "",
    "3. Replace a range of lines:",
    "   {\"path\": \"example.txt\", \"start\": 3, \"stop\": 7, \"content\": \"New content replacing lines 3-7\"}",
    "",
    "4. Remove a range of lines:",
    "   {\"path\": \"example.txt\", \"start\": 2, \"stop\": 5}",
    "",
    "5. Replace entire file contents:",
    "   {\"path\": \"example.txt\", \"content\": \"New file contents\"}",
    "",
    "6. Update from a specific line to the end of the file:",
    "   {\"path\": \"example.txt\", \"start\": 10, \"content\": \"New content from line 10 onwards\"}",
    "",
    "7. Update from the beginning of the file to a specific line:",
    "   {\"path\": \"example.txt\", \"stop\": 6, \"content\": \"New content for first 5 lines\"}",
    "",
    "Note: Always use specific line numbers based on the current file content. Avoid using arbitrarily large numbers for start or stop.",
}

var ModifyFile = api.ToolSpec{
	Name:        "modify_file",
	Description: strings.Join(MODIFY_FILE_DESCRIPTION, "\n"),
	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",
			Type:        "integer",
			Description: `Start line of the range to modify (inclusive). If omitted, the beginning of the file is implied.`,
		},
		{
			Name:        "stop",
			Type:        "integer",
			Description: `End line of the range to modify (inclusive). If omitted, the end of the file is implied.`,
		},
		{
			Name:        "content",
			Type:        "string",
			Description: "Content to insert/replace at the range defined by `start` and `stop`. If omitted, the range is removed.",
		},
	},
	Impl: func(tool *api.ToolSpec, args map[string]interface{}) (string, error) {
		tmp, ok := args["path"]
		if !ok {
			return "", fmt.Errorf("path parameter to modify_file was not included.")
		}
		path, ok := tmp.(string)
		if !ok {
			return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
		}
		var start int
		tmp, ok = args["start"]
		if ok {
			tmp, ok := tmp.(float64)
			if !ok {
				return "", fmt.Errorf("Invalid start in function arguments: %v", tmp)
			}
			start = int(tmp)
		}
		var stop int
		tmp, ok = args["stop"]
		if ok {
			tmp, ok := tmp.(float64)
			if !ok {
				return "", fmt.Errorf("Invalid stop in function arguments: %v", tmp)
			}
			stop = 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 := fileModifyContents(path, start, stop, content)
		ret, err := result.ToJson()
		if err != nil {
			return "", fmt.Errorf("Could not serialize result: %v", err)
		}
		return ret, nil
	},
}


func fileModifyContents(path string, startLine int, stopLine 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{}
    }

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

    // If both start and stop are unset, update the entire file
    if startLine == 0 && stopLine == 0 {
        lines = contentLines
    } else {
        if startLine < 1 {
            startLine = 1
        }
        if stopLine == 0 || stopLine > len(lines) {
            stopLine = len(lines)
        }

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

        // Handle insertion case
        if startLine == stopLine {
            lines = append(before, append(contentLines, lines[startLine-1:]...)...)
        } else {
            // If content is omitted, remove the specified range
            if content == "" {
                lines = append(before, after...)
            } else {
                lines = append(before, append(contentLines, after...)...)
            }
        }
    }

    newContent := strings.Join(lines, "\n")

    // 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: util.AddLineNumbers(newContent)}
}