package cmd

import (
	"context"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"

	keepapi "google.golang.org/api/keep/v1"

	"github.com/steipete/gogcli/internal/config"
	"github.com/steipete/gogcli/internal/googleapi"
	"github.com/steipete/gogcli/internal/outfmt"
	"github.com/steipete/gogcli/internal/ui"
)

var newKeepServiceWithSA = googleapi.NewKeepWithServiceAccount

type KeepCmd struct {
	ServiceAccount string `name:"service-account" help:"Path to service account JSON file"`
	Impersonate    string `name:"impersonate" help:"Email to impersonate (required with service-account)"`

	List       KeepListCmd       `cmd:"" default:"withargs" help:"List notes"`
	Get        KeepGetCmd        `cmd:"" name:"get" help:"Get a note"`
	Search     KeepSearchCmd     `cmd:"" name:"search" help:"Search notes by text (client-side)"`
	Attachment KeepAttachmentCmd `cmd:"" name:"attachment" help:"Download an attachment"`
}

type KeepListCmd struct {
	Max    int64  `name:"max" help:"Max results" default:"100"`
	Page   string `name:"page" help:"Page token"`
	Filter string `name:"filter" help:"Filter expression (e.g. 'create_time > \"2024-01-01T00:00:00Z\"')"`
}

func (c *KeepListCmd) Run(ctx context.Context, flags *RootFlags, keep *KeepCmd) error {
	u := ui.FromContext(ctx)

	svc, err := getKeepService(ctx, flags, keep)
	if err != nil {
		return err
	}

	call := svc.Notes.List().PageSize(c.Max).PageToken(c.Page)

	if c.Filter != "" {
		call = call.Filter(c.Filter)
	}

	resp, err := call.Do()
	if err != nil {
		return err
	}

	if outfmt.IsJSON(ctx) {
		return outfmt.WriteJSON(os.Stdout, map[string]any{
			"notes":         resp.Notes,
			"nextPageToken": resp.NextPageToken,
		})
	}

	if len(resp.Notes) == 0 {
		u.Err().Println("No notes")
		return nil
	}

	w, flush := tableWriter(ctx)
	defer flush()
	fmt.Fprintln(w, "NAME\tTITLE\tUPDATED")
	for _, n := range resp.Notes {
		title := n.Title
		if title == "" {
			title = noteSnippet(n)
		}
		fmt.Fprintf(w, "%s\t%s\t%s\n", n.Name, title, n.UpdateTime)
	}
	printNextPageHint(u, resp.NextPageToken)
	return nil
}

func noteSnippet(n *keepapi.Note) string {
	if n.Body == nil || n.Body.Text == nil {
		return "(no content)"
	}
	text := n.Body.Text.Text
	if len(text) > 50 {
		text = text[:50] + "..."
	}
	text = strings.ReplaceAll(text, "\n", " ")
	return text
}

func noteContains(n *keepapi.Note, query string) bool {
	query = strings.ToLower(query)
	if strings.Contains(strings.ToLower(n.Title), query) {
		return true
	}
	if n.Body != nil && n.Body.Text != nil {
		if strings.Contains(strings.ToLower(n.Body.Text.Text), query) {
			return true
		}
	}
	return false
}

type KeepSearchCmd struct {
	Query string `arg:"" name:"query" help:"Text to search for in title and body"`
	Max   int64  `name:"max" help:"Max results to fetch before filtering" default:"500"`
}

func (c *KeepSearchCmd) Run(ctx context.Context, flags *RootFlags, keep *KeepCmd) error {
	u := ui.FromContext(ctx)

	if strings.TrimSpace(c.Query) == "" {
		return fmt.Errorf("search query cannot be empty")
	}

	svc, err := getKeepService(ctx, flags, keep)
	if err != nil {
		return err
	}

	var allNotes []*keepapi.Note
	pageToken := ""

	for {
		call := svc.Notes.List().PageSize(c.Max).PageToken(pageToken)
		resp, err := call.Do()
		if err != nil {
			return err
		}

		for _, n := range resp.Notes {
			if noteContains(n, c.Query) {
				allNotes = append(allNotes, n)
			}
		}

		if resp.NextPageToken == "" {
			break
		}
		pageToken = resp.NextPageToken
	}

	if outfmt.IsJSON(ctx) {
		return outfmt.WriteJSON(os.Stdout, map[string]any{
			"notes": allNotes,
			"query": c.Query,
			"count": len(allNotes),
		})
	}

	if len(allNotes) == 0 {
		u.Err().Printf("No notes matching %q", c.Query)
		return nil
	}

	w, flush := tableWriter(ctx)
	defer flush()
	fmt.Fprintln(w, "NAME\tTITLE\tUPDATED")
	for _, n := range allNotes {
		title := n.Title
		if title == "" {
			title = noteSnippet(n)
		}
		fmt.Fprintf(w, "%s\t%s\t%s\n", n.Name, title, n.UpdateTime)
	}
	u.Err().Printf("Found %d notes matching %q", len(allNotes), c.Query)
	return nil
}

type KeepGetCmd struct {
	NoteID string `arg:"" name:"noteId" help:"Note ID or name (e.g. notes/abc123)"`
}

func (c *KeepGetCmd) Run(ctx context.Context, flags *RootFlags, keep *KeepCmd) error {
	u := ui.FromContext(ctx)

	svc, err := getKeepService(ctx, flags, keep)
	if err != nil {
		return err
	}

	name := c.NoteID
	if !strings.HasPrefix(name, "notes/") {
		name = "notes/" + name
	}

	note, err := svc.Notes.Get(name).Do()
	if err != nil {
		return err
	}

	if outfmt.IsJSON(ctx) {
		return outfmt.WriteJSON(os.Stdout, map[string]any{"note": note})
	}

	u.Out().Printf("name\t%s", note.Name)
	u.Out().Printf("title\t%s", note.Title)
	u.Out().Printf("created\t%s", note.CreateTime)
	u.Out().Printf("updated\t%s", note.UpdateTime)
	u.Out().Printf("trashed\t%v", note.Trashed)
	if note.Body != nil && note.Body.Text != nil {
		u.Out().Println("")
		u.Out().Println(note.Body.Text.Text)
	}
	if len(note.Attachments) > 0 {
		u.Out().Println("")
		u.Out().Printf("attachments\t%d", len(note.Attachments))
		for _, a := range note.Attachments {
			u.Out().Printf("  %s\t%s", a.Name, a.MimeType)
		}
	}
	return nil
}

type KeepAttachmentCmd struct {
	AttachmentName string `arg:"" name:"attachmentName" help:"Attachment name (e.g. notes/abc123/attachments/xyz789)"`
	MimeType       string `name:"mime-type" help:"MIME type of attachment (e.g. image/jpeg)" default:"application/octet-stream"`
	Out            string `name:"out" help:"Output file path (default: attachment filename or ID)"`
}

func (c *KeepAttachmentCmd) Run(ctx context.Context, flags *RootFlags, keep *KeepCmd) error {
	u := ui.FromContext(ctx)

	svc, err := getKeepService(ctx, flags, keep)
	if err != nil {
		return err
	}

	name := c.AttachmentName
	if !strings.Contains(name, "/attachments/") {
		return fmt.Errorf("invalid attachment name format, expected: notes/<noteId>/attachments/<attachmentId>")
	}

	resp, err := svc.Media.Download(name).MimeType(c.MimeType).Download()
	if err != nil {
		return fmt.Errorf("download attachment: %w", err)
	}
	defer resp.Body.Close()

	outPath := c.Out
	if outPath == "" {
		parts := strings.Split(name, "/")
		outPath = parts[len(parts)-1]
	}

	if dir := filepath.Dir(outPath); dir != "." {
		if mkdirErr := os.MkdirAll(dir, 0o700); mkdirErr != nil && !os.IsExist(mkdirErr) {
			return fmt.Errorf("create output directory: %w", mkdirErr)
		}
	}

	f, err := os.Create(outPath) //nolint:gosec // user-provided output path
	if err != nil {
		return fmt.Errorf("create output file: %w", err)
	}
	defer f.Close()

	written, err := io.Copy(f, resp.Body)
	if err != nil {
		return fmt.Errorf("write attachment: %w", err)
	}

	if outfmt.IsJSON(ctx) {
		return outfmt.WriteJSON(os.Stdout, map[string]any{
			"downloaded": true,
			"path":       outPath,
			"bytes":      written,
		})
	}

	u.Out().Printf("path\t%s", outPath)
	u.Out().Printf("bytes\t%d", written)
	return nil
}

func getKeepService(ctx context.Context, flags *RootFlags, keepCmd *KeepCmd) (*keepapi.Service, error) {
	if keepCmd.ServiceAccount != "" {
		if keepCmd.Impersonate == "" {
			return nil, fmt.Errorf("--impersonate is required when using --service-account")
		}
		return newKeepServiceWithSA(ctx, keepCmd.ServiceAccount, keepCmd.Impersonate)
	}

	account, err := requireAccount(flags)
	if err != nil {
		return nil, err
	}

	genericSAPath, err := config.ServiceAccountPath(account)
	if err != nil {
		return nil, err
	}
	if _, statErr := os.Stat(genericSAPath); statErr == nil {
		return newKeepServiceWithSA(ctx, genericSAPath, account)
	}

	saPath, err := config.KeepServiceAccountPath(account)
	if err != nil {
		return nil, err
	}

	if _, statErr := os.Stat(saPath); statErr == nil {
		return newKeepServiceWithSA(ctx, saPath, account)
	}

	legacyPath, legacyErr := config.KeepServiceAccountLegacyPath(account)
	if legacyErr == nil {
		if _, statErr := os.Stat(legacyPath); statErr == nil {
			return newKeepServiceWithSA(ctx, legacyPath, account)
		}
	}

	return nil, usage("Keep is Workspace-only and requires a service account. Configure it with: gog auth service-account set <email> --key <service-account.json> (or legacy: gog auth keep <email> --key <service-account.json>)")
}