package main

import (
	"sort"
	"strings"
	"time"
)

type RepoInfo struct {
	Name        string
	Path        string
	GitDir      string
	Description string
	Owner       string
	LastUpdated time.Time
	Git         *gitCLIBackend
}

type CommitInfo struct {
	Hash        string
	ShortHash   string
	Subject     string
	Body        string
	Author      string
	AuthorEmail string
	AuthorDate  time.Time
	Parents     []string
}

type TreeEntryInfo struct {
	Name  string
	IsDir bool
	Size  int64
	Mode  string
	Hash  string
}

type BlobInfo struct {
	Name     string
	Size     int64
	IsBinary bool
	Lines    []string
	Content  string
}

type RefInfo struct {
	Name      string
	Hash      string
	ShortHash string
	Subject   string
	Author    string
	Date      time.Time
	IsTag     bool
}

type DiffFile struct {
	OldName  string
	NewName  string
	Status   string
	Hunks    []DiffHunk
	IsBinary bool
	Stats    DiffStats
}

type DiffStats struct {
	Added   int
	Deleted int
}

type DiffHunk struct {
	Header string
	Lines  []DiffLine
}

type DiffLine struct {
	Type    string // "context", "add", "del"
	Content string
	OldNum  int
	NewNum  int
}

type TreeNode struct {
	Name     string
	IsDir    bool
	Size     int64
	Path     string
	Depth    int
	IsOpen   bool
	IsActive bool
}

const maxBlobDisplaySize = 1 << 20 // 1MB
const diffContextLines = 5
const maxDiffFiles = 256 // max files rendered per commit

func sortTreeEntries(entries []TreeEntryInfo) {
	sort.Slice(entries, func(i, j int) bool {
		if entries[i].IsDir != entries[j].IsDir {
			return entries[i].IsDir
		}
		return entries[i].Name < entries[j].Name
	})
}

// collapseContext takes a flat list of diff lines and splits them into
// hunks, keeping only diffContextLines of context around add/del lines.
func collapseContext(lines []DiffLine) []DiffHunk {
	if len(lines) == 0 {
		return nil
	}

	// Mark which lines to keep: diffContextLines around each changed line.
	keep := make([]bool, len(lines))
	for i, l := range lines {
		if l.Type == "add" || l.Type == "del" {
			start := i - diffContextLines
			if start < 0 {
				start = 0
			}
			end := i + diffContextLines
			if end >= len(lines) {
				end = len(lines) - 1
			}
			for j := start; j <= end; j++ {
				keep[j] = true
			}
		}
	}

	// Build hunks from contiguous kept ranges.
	var hunks []DiffHunk
	var current *DiffHunk
	for i, l := range lines {
		if keep[i] {
			if current == nil {
				current = &DiffHunk{}
			}
			current.Lines = append(current.Lines, l)
		} else {
			if current != nil {
				hunks = append(hunks, *current)
				current = nil
			}
		}
	}
	if current != nil {
		hunks = append(hunks, *current)
	}

	return hunks
}

var mimeTypes = map[string]string{
	".txt":  "text/plain; charset=utf-8",
	".md":   "text/plain; charset=utf-8",
	".go":   "text/plain; charset=utf-8",
	".rs":   "text/plain; charset=utf-8",
	".py":   "text/plain; charset=utf-8",
	".js":   "text/plain; charset=utf-8",
	".ts":   "text/plain; charset=utf-8",
	".c":    "text/plain; charset=utf-8",
	".h":    "text/plain; charset=utf-8",
	".css":  "text/css; charset=utf-8",
	".html": "text/html; charset=utf-8",
	".json": "application/json",
	".xml":  "application/xml",
	".png":  "image/png",
	".jpg":  "image/jpeg",
	".jpeg": "image/jpeg",
	".gif":  "image/gif",
	".svg":  "image/svg+xml",
	".pdf":  "application/pdf",
}

func mimeFromPath(path string) string {
	idx := strings.LastIndex(path, ".")
	if idx < 0 {
		return ""
	}
	ext := strings.ToLower(path[idx:])
	if t, ok := mimeTypes[ext]; ok {
		return t
	}
	return ""
}