package main

import (
	"context"
	"errors"
	"log/slog"
	"net/http"
	"net/url"
	"os"
	"path/filepath"

	"github.com/gin-gonic/gin"
)

// pathParam pulls the URL-encoded :rel out of the Gin context and
// unescapes it. UseRawPath is on at the router level (see main.go) so the
// raw value still carries `%2F` for nested paths; we decode here.
func pathParam(c *gin.Context, key string) (string, bool) {
	raw := c.Param(key)
	if raw == "" {
		return "", false
	}
	dec, err := url.PathUnescape(raw)
	if err != nil {
		return "", false
	}
	return dec, true
}

type folderCreateBody struct {
	Path string `json:"path"`
}

func handleFolderCreate(cfg *Config, pp *ppClient) gin.HandlerFunc {
	return func(c *gin.Context) {
		token := ctxToken(c)
		var body folderCreateBody
		if err := c.ShouldBindJSON(&body); err != nil || body.Path == "" {
			c.JSON(http.StatusBadRequest, gin.H{"error": "path required"})
			return
		}
		abs, err := resolveUnderRoot(cfg.OriginalsRoot, body.Path, false)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid path"})
			return
		}
		if _, err := os.Stat(abs); err == nil {
			c.JSON(http.StatusConflict, gin.H{"error": "already exists"})
			return
		} else if !errors.Is(err, os.ErrNotExist) {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		if err := os.Mkdir(abs, 0o755); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		rel, _ := filepath.Rel(cfg.OriginalsRoot, abs)
		slog.Info("folder.create", "path", rel)
		go fireReindex(cfg, pp, token, "/"+filepath.Dir(rel))
		c.JSON(http.StatusOK, gin.H{"ok": true, "path": rel})
	}
}

type folderRenameBody struct {
	NewName string `json:"newName"`
}

func handleFolderRename(cfg *Config, pp *ppClient) gin.HandlerFunc {
	return func(c *gin.Context) {
		token := ctxToken(c)
		rel, ok := pathParam(c, "rel")
		if !ok {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid path"})
			return
		}
		var body folderRenameBody
		if err := c.ShouldBindJSON(&body); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid json"})
			return
		}
		newName, ok := sanitizeFilename(body.NewName)
		if !ok {
			c.JSON(http.StatusBadRequest, gin.H{"error": "newName must be a plain dirname"})
			return
		}
		oldAbs, err := resolveUnderRoot(cfg.OriginalsRoot, rel, true)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid path"})
			return
		}
		st, err := os.Stat(oldAbs)
		if err != nil || !st.IsDir() {
			c.JSON(http.StatusBadRequest, gin.H{"error": "not a directory"})
			return
		}
		newAbs := filepath.Join(filepath.Dir(oldAbs), newName)
		if _, err := os.Stat(newAbs); err == nil {
			c.JSON(http.StatusConflict, gin.H{"error": "target already exists"})
			return
		} else if !errors.Is(err, os.ErrNotExist) {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		if !sameOrUnder(newAbs, cfg.OriginalsRoot) {
			c.JSON(http.StatusBadRequest, gin.H{"error": "target escapes root"})
			return
		}
		if err := os.Rename(oldAbs, newAbs); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		oldRel, _ := filepath.Rel(cfg.OriginalsRoot, oldAbs)
		newRel, _ := filepath.Rel(cfg.OriginalsRoot, newAbs)
		slog.Info("folder.rename", "from", oldRel, "to", newRel)
		go fireReindex(cfg, pp, token, "/"+filepath.Dir(oldRel))
		c.JSON(http.StatusOK, gin.H{
			"ok":      true,
			"oldPath": oldRel,
			"newPath": newRel,
		})
	}
}

func handleFolderDelete(cfg *Config, pp *ppClient) gin.HandlerFunc {
	return func(c *gin.Context) {
		token := ctxToken(c)
		rel, ok := pathParam(c, "rel")
		if !ok {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid path"})
			return
		}
		abs, err := resolveUnderRoot(cfg.OriginalsRoot, rel, true)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid path"})
			return
		}
		if abs == cfg.OriginalsRoot {
			c.JSON(http.StatusBadRequest, gin.H{"error": "refuse to delete root"})
			return
		}
		st, err := os.Stat(abs)
		if err != nil || !st.IsDir() {
			c.JSON(http.StatusBadRequest, gin.H{"error": "not a directory"})
			return
		}
		entries, err := os.ReadDir(abs)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		if len(entries) > 0 {
			c.JSON(http.StatusConflict, gin.H{"error": "directory not empty"})
			return
		}
		if err := os.Remove(abs); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		slog.Info("folder.delete", "path", rel)
		go fireReindex(cfg, pp, token, "/"+filepath.Dir(rel))
		c.JSON(http.StatusOK, gin.H{"ok": true, "path": rel})
	}
}

// fireReindex wraps pp.reindex with logging and a detached context so
// it can run in a goroutine after the response has gone out. The Node
// prototype kicks reindex with `void reindex(...)` and never awaits;
// matching that here keeps the apparent latency of mutating endpoints
// low (PhotoPrism's index can take seconds on a big folder).
func fireReindex(_ *Config, pp *ppClient, token, parentRel string) {
	// pp.call's client already enforces a 60s timeout, so the parent
	// context can be detached from the request — the handler has long
	// since written its response.
	if err := pp.reindex(context.Background(), token, parentRel); err != nil {
		slog.Warn("reindex failed", "path", parentRel, "err", err)
	}
}