// Package activity reads the autotrack staging log and calendar events for
// display in the grid's ACTIVITY column. All parsing is tolerant: a bad line,
// missing file, or missing helper never fails the view.
package activity

import (
	"bufio"
	"encoding/json"
	"os"
	"path/filepath"
	"time"
)

// Segment is one recorded activity span from the daily jsonl log.
type Segment struct {
	Start, End              time.Time
	App, Title, URL, Domain string
	Idle                    bool
}

// rawSegment mirrors one jsonl line; timestamps stay strings for tolerant
// parsing (secs is derivable and unused by the reader).
type rawSegment struct {
	Start  string `json:"start"`
	End    string `json:"end"`
	App    string `json:"app"`
	Title  string `json:"title"`
	URL    string `json:"url"`
	Domain string `json:"domain"`
	Idle   bool   `json:"idle"`
}

// stampLayout matches the daemon's isoformat(timespec="seconds") local stamps.
const stampLayout = "2006-01-02T15:04:05"

// LoadDay reads activity-<date>.jsonl under dataDir. Malformed lines are
// skipped — one bad row never fails the view. A missing file (or empty
// dataDir) yields an empty slice with no error.
func LoadDay(dataDir, date string) ([]Segment, error) {
	if dataDir == "" {
		return nil, nil
	}
	f, err := os.Open(filepath.Join(dataDir, "activity-"+date+".jsonl"))
	if err != nil {
		return nil, nil
	}
	defer f.Close()
	var segs []Segment
	sc := bufio.NewScanner(f)
	sc.Buffer(make([]byte, 0, 64*1024), 1024*1024) // long window titles/URLs
	for sc.Scan() {
		var r rawSegment
		if err := json.Unmarshal(sc.Bytes(), &r); err != nil {
			continue
		}
		start, err := time.ParseInLocation(stampLayout, r.Start, time.Local)
		if err != nil {
			continue
		}
		end, err := time.ParseInLocation(stampLayout, r.End, time.Local)
		if err != nil {
			continue
		}
		segs = append(segs, Segment{
			Start: start, End: end,
			App: r.App, Title: r.Title, URL: r.URL, Domain: r.Domain, Idle: r.Idle,
		})
	}
	return segs, nil
}