import OrgSwift
import SwiftUI

/// Renders prepared blocks. All the org work happened in ``OrgLayoutBuilder``; this is
/// layout only.
struct OrgBlockListView: View {
    let blocks: [OrgBlock]

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            ForEach(Array(blocks.enumerated()), id: \.offset) { _, block in
                OrgBlockView(block: block)
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

struct OrgBlockView: View {
    let block: OrgBlock
    @Environment(\.orgMath) private var math

    var body: some View {
        switch block {
        case .heading(let text, let level):
            orgText(text, math: math)
                .padding(.top, level <= 2 ? 8 : 2)
                .fixedSize(horizontal: false, vertical: true)

        case .paragraph(let text):
            orgText(text, math: math)
                .fixedSize(horizontal: false, vertical: true)

        case .code(let code):
            ScrollView(.horizontal) {
                Text(code)
                    .textSelection(.enabled)
                    .padding(10)
            }
            .background(
                Color.secondary.opacity(0.12),
                in: RoundedRectangle(cornerRadius: 4)
            )

        case .quote(let blocks):
            HStack(spacing: 10) {
                RoundedRectangle(cornerRadius: 2)
                    .fill(.tertiary)
                    .frame(width: 3)
                OrgBlockListView(blocks: blocks)
                    .foregroundStyle(.secondary)
            }
            .fixedSize(horizontal: false, vertical: true)

        case .center(let blocks):
            OrgBlockListView(blocks: blocks)
                .multilineTextAlignment(.center)
                .frame(maxWidth: .infinity, alignment: .center)

        case .verse(let lines):
            // Verse keeps its line breaks; that is the whole point of the block.
            VStack(alignment: .leading, spacing: 0) {
                ForEach(Array(lines.enumerated()), id: \.offset) { _, line in
                    orgText(line, math: math).fixedSize(horizontal: false, vertical: true)
                }
            }

        case .special(_, let blocks):
            OrgBlockListView(blocks: blocks)

        case .list(let list):
            OrgListView(list: list)

        case .table(let table):
            OrgTableView(table: table)

        case .image(let source, let alt, let caption):
            VStack(alignment: .leading, spacing: 4) {
                AsyncImage(url: source) { phase in
                    switch phase {
                    case .success(let image):
                        image.resizable().scaledToFit()
                    case .failure:
                        Text(alt.isEmpty ? source.lastPathComponent : alt)
                            .font(.footnote)
                            .foregroundStyle(.secondary)
                    default:
                        ProgressView()
                    }
                }
                .accessibilityLabel(alt)
                if let caption {
                    orgText(caption, math: math).foregroundStyle(.secondary)
                }
            }

        case .badges(let badges):
            OrgBadgeRowView(badges: badges)

        case .captioned(let caption, let blocks):
            VStack(alignment: .leading, spacing: 4) {
                OrgBlockListView(blocks: blocks)
                if let caption {
                    orgText(caption, math: math).foregroundStyle(.secondary)
                }
            }

        case .rule:
            Divider()

        case .math(let expression):
            OrgMathBlockView(math: expression)
        }
    }
}