# [SKRIP 5.2: Ekspresi di dalam alat Processing: Field calculator, Extract by expression, label]
# Penulis: Badar Mubarok Yogaswara
import processing
from qgis.core import (QgsProject, QgsVectorLayer, QgsExpression, QgsExpressionContext,
                       QgsExpressionContextUtils)

DATA = "D:/Latihan/paket-i4"
HASIL = "D:/Latihan/hasil_i4"

proyek = QgsProject.instance()
batas = QgsVectorLayer(DATA + "/Batas_KPH.gpkg", "Batas_KPH", "ogr")
hotspot = QgsVectorLayer(DATA + "/Hotspot_Nasional.gpkg", "Hotspot_Nasional", "ogr")
proyek.addMapLayer(batas)
proyek.addMapLayer(hotspot)         # wajib ada di proyek agar aggregate() menemukannya

# 1. Menambah dua kolom baru dengan ekspresi
tahap1 = processing.run("native:fieldcalculator", {
    "INPUT": batas, "FIELD_NAME": "LUAS_HA", "FIELD_TYPE": 0,          # 0 = desimal
    "FIELD_LENGTH": 10, "FIELD_PRECISION": 2,
    "FORMULA": "round($area / 10000, 2)", "OUTPUT": "TEMPORARY_OUTPUT"})["OUTPUT"]
tahap2 = processing.run("native:fieldcalculator", {
    "INPUT": tahap1, "FIELD_NAME": "JML_HOTSPOT", "FIELD_TYPE": 1,     # 1 = bilangan bulat
    "FIELD_LENGTH": 5, "FIELD_PRECISION": 0,
    "FORMULA": "aggregate('Hotspot_Nasional', 'count', \"ID_Titik\", "
               "intersects($geometry, geometry(@parent)))",
    "OUTPUT": "TEMPORARY_OUTPUT"})["OUTPUT"]
tahap2.setName("Batas_KPH_Ringkas")
proyek.addMapLayer(tahap2)
print("Kolom:", [f.name() for f in tahap2.fields()])
for f in tahap2.getFeatures():
    print("  ", f["NAMA_KPH"], f["LUAS_HA"], "ha;", f["JML_HOTSPOT"], "titik panas")

# 2. Memilih fitur dengan ekspresi lewat alat
rawan = processing.run("native:extractbyexpression", {
    "INPUT": tahap2, "EXPRESSION": '"JML_HOTSPOT" >= 5', "OUTPUT": "TEMPORARY_OUTPUT"})["OUTPUT"]
print("KPH dengan titik panas >= 5:", sorted(f["NAMA_KPH"] for f in rawan.getFeatures()))

# 3. Teks laporan satu KPH, dibentuk dengan ekspresi (cara yang sama dipakai label di layout)
teks = ("'LAPORAN ' || upper(\"NAMA_KPH\") || '\n' || 'Luas: ' || \"LUAS_HA\" || ' ha\n' || "
        "'Titik panas: ' || \"JML_HOTSPOT\" || ' titik'")
ekspresi = QgsExpression(teks)
for f in tahap2.getFeatures():
    c = QgsExpressionContext()
    c.appendScopes(QgsExpressionContextUtils.globalProjectLayerScopes(tahap2))
    c.setFeature(f)
    print(ekspresi.evaluate(c))
    print("---")